The Language of Time
A practical glossary of the concepts we use to describe when things happen, how long they last, how they repeat, and how they become part of a life.
Five ways to think about time
- When?Dates, instants and timestamps.
- How long?Durations, intervals and lifespans.
- In what order?Sequence, chronology and before/after.
- What changes or repeats?Rhythms, cycles, recurrence and development.
- What does it mean to us?Memory, anticipation, milestones, chapters and legacy.
Chronodromia brings these questions together in one personal timeline.
Essential Time: Points & Spans
The basic vocabulary of time: the words we reach for when we say when something happens, how long it lasts, and where it sits relative to now.
Instant
A precise point in time with no duration of its own.
Distinct fromAn instant is mathematical; it names the point. A moment names what the point means to us.
Example14:02:07 on 9 October 2026 is an instant.
Moment
A point in time recognised for its significance rather than its precision.
Distinct fromUnlike an instant, a moment carries meaning; it is a point in time we notice.
ExampleThe moment a child is born; the moment a decade-long job ends.
Date
A named day within a calendar system.
Distinct fromA date identifies a whole day. A timestamp can identify an exact instant inside it.
Example4 July is a date; the second the fireworks start is an instant.
Event
Something that happens, or happened, at a point in time or across a bounded span.
Distinct fromIn everyday use an event can be a point (a birth) or a span (a holiday). Chronodromia keeps both.
Duration
How long something lasts: the amount of elapsed time between a beginning and an end.
Distinct fromDuration measures the length of time. An interval identifies the bounded span itself.
ExampleA friendship that has lasted twelve years has a duration of twelve years.
In ChronodromiaDuration describes how long ago something happened, how much time remains, and how long an active interval has been running.
Interval
A span of time bounded by a beginning and an end.
ExampleA trip lasting from 4 June to 18 June is an interval.
In ChronodromiaJobs, trips, relationships, pregnancies and other experiences with a meaningful start and end can be represented as intervals.
Timeline
An arrangement of events along a line of time, showing where each one sits relative to the others.
In ChronodromiaYour timeline places past events behind you and future events ahead, with the present always moving through it.
Chronology
The order in which events happened, and the practice of arranging them in that order.
Distinct fromChronology is about sequence, not duration.
ExamplePutting a life in chronological order tells you what came first, not how long anything lasted.
Past
The region of time that has already elapsed, fixed and no longer changeable.
In ChronodromiaPast events tell you how long it has been since something happened.
Present
The moving boundary between past and future: the only region of time we can act within.
Distinct fromThe present is less a point than a horizon: it is always arriving and always leaving.
Future
The region of time not yet reached: open, expected and unwritten.
In ChronodromiaFuture events tell you how long remains until something happens.
Elapsed Time
The duration that has passed since a point in the past or the start of an interval.
ExampleIt has been 14 years since you moved house.
In ChronodromiaElapsed time powers count-up answers like “3,652 days since you started this job.”
Remaining Time
The duration between now and a point still ahead.
ExampleThere are 62 days until the wedding.
In ChronodromiaRemaining time powers countdowns to future events, from birthdays to deadlines.
Change & Repetition
Time does more than pass; it returns. These words describe the patterns, thresholds and rhythms that make some moments repeat and others mark irreversible change.
Occurrence
One realised instance of a recurring event.
Distinct fromA birthday is the event; your birthday in 2026 is an occurrence of it.
Recurrence
A pattern or rule by which something happens again.
Distinct fromThe event is what repeats; the recurrence is the rule that repeats it.
ExampleEvery year on the same date; every second Tuesday; every 28 days.
In ChronodromiaRecurrence rules let one event (a birthday, a bill, a habit) generate every occurrence on your timeline.
Cycle
A sequence that returns to its starting point and repeats.
ExampleThe seasons, the phases of the moon, and the body’s menstrual cycle are all cycles.
Period
A length of time forming a complete unit or phase; also one pass of a repeating cycle.
Distinct fromA duration answers “how long”; a period names a bounded phase that can open, run and close.
Rhythm
A regular pattern of recurrence in time.
ExampleA heartbeat, a weekly routine and a monthly cycle are rhythms at very different scales.
Frequency
How often something repeats within a unit of time.
ExampleA haircut every six weeks has a frequency of roughly nine times a year.
Milestone
A meaningful threshold or point marking progress or change.
ExampleYour 10,000th day alive, a tenth anniversary, or one full year in a new city.
In ChronodromiaMeaningful thresholds derived from time can surface as milestones on your timeline.
Anniversary
The yearly recurrence of a significant date.
Distinct fromEvery anniversary is a recurrence, but not every recurrence is an anniversary; the word is reserved for the yearly cycle.
Streak
An unbroken run of repeated occurrences.
ExampleWriting every day for a hundred days is a streak; one missed day ends it.
In ChronodromiaDaily activity can form streaks, turning repetition into something worth protecting.
Transition
A passage from one state, phase or chapter to another.
ExampleGraduation, a move abroad, and recovery after surgery are transitions: spans where life is changing shape.
Personal & Life Time
The time we actually live in is not clock time; it is memory, expectation and meaning. These are the words for time as a life experiences it.
Memory
The mind’s record of experienced events, the faculty that lets the past persist into the present.
Anticipation
The experience of expecting a future event, the future reaching back into the present.
ExampleCounting down to a reunion is anticipation doing its work: the event is future, but the feeling is now.
Life Event
An event significant enough to mark a life: births, moves, relationships, achievements, losses.
In ChronodromiaYour timeline is built from life events: the points and spans that make a life legible.
Chapter
A named span of a life story with a distinct character, defined less by dates than by meaning.
Example“The Melbourne years.” “The new-parent era.” Chapters are intervals with names.
Personal Chronology
The ordered record of one person’s life events: a chronology with an audience of one.
In ChronodromiaChronodromia is built to hold a personal chronology: what happened, when, and how it fits together.
Time Perspective
A person’s habitual orientation toward the past, present or future.
ExampleSome people plan by looking backward at experience; others live almost entirely in what comes next.
Temporal Context
The surrounding time that gives a moment its meaning: its date, era, life stage and what came before.
ExampleA first day at a new job means something different at twenty than at fifty.
Birthday
The anniversary of a birth, the most familiar personal recurrence of all.
In ChronodromiaBirthdays are recurring events: the event is the person’s birth date; each year produces a new occurrence.
Lifespan
The full interval of a life, from birth to death.
Mortality
The fact that a lifespan is bounded: the boundary that gives time its weight.
ExampleKnowing a life is finite is what turns elapsed time from a number into a question.
Legacy
What remains of a life, era or chapter after it ends, carried forward in people, work and memory.
Civil & Calendar Time
Clocks and calendars are agreements, not physics. These are the words for the negotiated time that schedules actually run on.
Calendar
A system for naming, numbering and organising days.
ExampleThe Gregorian calendar is the civil standard across most of the world; many cultures keep others alongside it.
Civil Time
The legally agreed time used for daily life in a region, set by calendars, time zones and clock conventions.
Distinct fromCivil time is a social contract: it answers “what time is it here?” not “how much time has passed?”
Timestamp
A precise recorded position in time, usually resolved to the second or finer.
Local Time
The clock time actually observed at a particular place.
Time Zone
A region of the Earth that shares the same official clock time.
ExampleWhen it is 9 a.m. in Sydney it is still the previous afternoon in London: same instant, different local time.
In ChronodromiaEvents anchored to a time zone stay correct in local time even when you travel.
UTC
Coordinated Universal Time, the global reference time from which every time zone is defined as an offset.
ExampleSydney runs at UTC+11 during daylight saving; London sits at UTC+0 in winter.
Daylight Saving Time
The seasonal shift of local clock time, usually by one hour, to move daylight into the evening.
ExampleTwice a year, clocks jump or fall back an hour; the sun does not move, only the agreement does.
Leap Year
A year containing an extra day, 29 February, keeping the calendar aligned with Earth’s orbit.
ExampleA person born on 29 February gets a true birthday only in leap years.
Biological & Cyclic Time
Bodies keep time too. These words cover the internal clocks and longer cycles that run underneath the calendar.
Circadian Rhythm
The roughly 24-hour internal cycle governing sleep, waking, hormones and body temperature.
ExampleJet lag is a circadian rhythm arguing with a new time zone.
Ultradian Rhythm
A biological cycle shorter than a day: heartbeats, breaths, sleep stages, waves of focus.
Infradian Rhythm
A biological cycle longer than a day: menstrual cycles and seasonal patterns among them.
In ChronodromiaLong personal cycles, like menstrual cycles, can be tracked as repeating periods rather than single events.
Chronological Age
Age measured as elapsed time since birth.
Distinct fromChronological age counts time; biological age describes the condition of the body itself.
In ChronodromiaA birth date turns chronological age into a live count: years, days, even heartbeats since you began.
Seasonality
Patterns that recur with the seasons of the year.
ExampleMood, energy, travel and even spending often run on seasonal cycles.
Deeper Time: Physics & Philosophy
For the curious: the words physics and philosophy use when they ask what time actually is. None of this is needed to use Chronodromia, but all of it is part of the territory.
Chronos
The Greek word for sequential, measurable time: time as quantity. Root of “chronology” and “Chronodromia”.
Distinct fromChronos asks “how much time?”; its counterpart Kairos asks “is this the right moment?”
Kairos
The Greek word for the opportune or significant moment: time as quality rather than quantity.
ExampleThe right moment to act, to speak, to begin: not any instant, but the fitting one.
Arrow of Time
The observed one-way direction of time: the past is fixed, the future is not, and nothing flows the other way.
Entropy
The measure of disorder in a system, and the physical tendency most often invoked to explain why time runs one way.
Spacetime
The four-dimensional fabric that combines space and time: the arena in which, according to relativity, all events occur.
Proper Time
The time measured by a clock travelling along its own path through spacetime; the time that actually elapses for you.
Time Dilation
The slowing of measured time at high velocity or in strong gravity, predicted by relativity and confirmed by experiment.
ExampleClocks on GPS satellites tick at a measurably different rate than clocks on Earth.
Mental Time Travel
The mind’s ability to re-experience the past and pre-experience the future: remembering and imagining in the first person.
Presentism
The philosophical position that only the present exists: the past has ceased, the future is not yet.
Eternalism
The philosophical position that past, present and future all equally exist: that time is laid out like space.
Temporal Passage
The felt sense that time flows: that events approach from the future, arrive, and recede into the past.
Distinct fromWhether time truly flows or only appears to is one of philosophy’s open questions.
How Chronodromia Uses Time
The words above belong to everyone. These belong to the app: Chronodromia’s own vocabulary, defined against the same concepts.
- Event
- A recorded point or span on your timeline, from a single date like a birth to a bounded experience like a job.
- Occurrence
- One realised instance of a recurring event. A birthday is the event; this year’s birthday is an occurrence.
- Interval
- An event with both a start and an end, used for jobs, travel, relationships and other bounded experiences.
- Period
- An interval currently in progress: an ongoing job, an active cycle. A period stays open until it ends, then becomes part of the past.
- Recurrence
- The rule by which an event repeats: yearly birthdays, weekly habits, monthly bills.
- Milestone
- A meaningful threshold derived from time: 10,000 days alive, one year since a move, a hundredth occurrence.
- History
- The full record of what happened to an event over time: its changes, resets and occurrences.
- Session
- A bounded span of actively tracked time within a single event.
- Check-in
- A question Chronodromia asks after something happened: did it happen again, how did it go, is it still going.
- Reminder
- A scheduled notification before or around an event.
- Time Lens
- A deeper view of a single moment in time: the events, cycles and sky surrounding one point on your timeline.