Time, Eras & Change — C1 Essential Words
Ten essential C1 words (Time) with the complete apparatus: pronunciation, simple definitions, natural American examples, collocations, family, the common mistake and spoken usage — plus a 15-question practice quiz. Mark your status on every word.
phase /feɪz/ noun C1 Time
Meaning: A stage in a process of development or change; one of the changing shapes of the Moon as seen from Earth.
Example: The project is in its final phase.
Another example: Teenagers go through a rebellious phase.
Collocations: a phase of · phase one · the final phase
Synonyms: stage, period, step
Word family: phases (n pl) · phase (v — usually 'phase in/out')
⚠ Common mistake: Parents console themselves with it ('just a phase'). Construction and moons share its stages; phasing OUT old tech is its verb branch.
🗣 In spoken American English: Its cousin 'faze' (disturb) is a different word — spellcheck's favorite confusion.
Register: Formal — time essential.
millennium /mɪˈleniəm/ noun C1 Time
Meaning: A period of one thousand years; the celebration of reaching a 1,000-year point.
Example: The bridge stood for a millennium.
Another example: The year 2000 began a new millennium.
Collocations: a millennium · the new millennium · for millennia
Synonyms: thousand years, age, era
Word family: millennia (n pl) · millennial (adj/n — the generation!)
⚠ Common mistake: Its plural is MILLENNIA; its people (millennials) are the generation reaching adulthood near the 2000 turn — one root, calendars and demography.
🗣 In spoken American English: Y2K fears made its arrival the most rehearsed midnight in history.
Register: Formal — time essential.
eternity /ɪˈtɜːrnəti/ noun C1 Time
Meaning: Time without end; forever. Also (informally) a very long time, usually of waiting.
Example: Some believe the soul lives for eternity.
Another example: The bus took an eternity to arrive.
Collocations: for eternity · an eternity · eternity ring
Synonyms: forever, infinity, endlessness
Antonyms: a moment
Word family: eternal (adj) · eternally (adv)
⚠ Common mistake: Theology's timescale and the queue's exaggeration share it — 'an eternity in line' is its daily uniform.
🗣 In spoken American English: Its rings (unbroken circles) borrow the symbol for weddings.
Register: Formal — time essential.
century /ˈsentʃəri/ noun C1 Time
Meaning: A period of one hundred years; also the name of each numbered hundred-year period (the 21st century = 2001–2100). Also 100 runs in cricket.
Example: The castle is a century old.
Another example: We live in the twenty-first century.
Collocations: a century · the 21st century · half a century
Synonyms: hundred years, age, era
Word family: centuries (n pl) · centennial (adj/n — 100th celebration)
⚠ Common mistake: Its off-by-one traps everyone: the 1900s are the TWENTIETH century. Towns celebrate centennials; tortoises live multiple ones.
🗣 In spoken American English: 'Turn of the century' always sounds classier than it is specific.
Register: Formal — time essential.
decade /ˈdekeɪd/ noun C1 Time
Meaning: A period of ten years, especially one of the named blocks (the 1990s is a decade).
Example: The city changed hugely in a decade.
Another example: She has taught for three decades.
Collocations: a decade · over the decade · the last decade
Synonyms: ten years, era, period
Word family: decades (n pl) · decadal (adj)
⚠ Common mistake: Culture gets nicknamed by them: the Roaring Twenties, the Swinging Sixties. 'Decades of experience' is résumés' heavy artillery.
🗣 In spoken American English: Its Greek cousin 'decathlon' counts tens in sports instead.
Register: Formal — time essential.
period /ˈpɪəriəd/ noun C1 Time
Meaning: A length or stretch of time with particular characteristics; also the punctuation mark at the end of a sentence (US), and a school lesson slot.
Example: The war period lasted six years.
Another example: End the sentence with a period.
Collocations: a period of · period of time · third period (class)
Synonyms: era, stretch, phase
Word family: periods (n pl) · periodic (adj) · periodically (adv)
⚠ Common mistake: American English calls the full stop a PERIOD — and says 'period' alone to end arguments ('That's it, period.'). British English keeps it for time and lessons.
🗣 In spoken American English: Geology divides Earth's history into its grandest versions.
Register: Formal — time essential.
instant /ˈɪnstənt/ noun / adjective C1 Time
Meaning: A very short moment of time; (adjective) happening immediately, or (of food) prepared very quickly with hot water.
Example: He recognized her in an instant.
Another example: Instant coffee, just add water.
Collocations: in an instant · an instant · instant noodles
Synonyms: moment, second, flash
Word family: instants (n pl) · instantly (adv) · instantaneous (adj)
⚠ Common mistake: Photography named a camera after it (Instax, Polaroid). Its food branch (noodles, coffee, oats) is modern patience measured in one word.
🗣 In spoken American English: 'In an instant' is its stage direction for magic and accidents alike.
Register: Neutral — time essential.
temporary /ˈtempərəri/ adjective C1 Time
Meaning: Lasting for only a limited time; not permanent.
Example: It's a temporary job for the summer.
Another example: The road is under temporary repair.
Collocations: a temporary job · temporary work · temporary closure
Synonyms: short-term, provisional, interim
Antonyms: permanent, lasting
Word family: temporarily (adv)
⚠ Common mistake: Say TEM-puh-RAIR-ee in the US — four syllables squeeze to three. Its job-market branch built the 'temp' worker (its noun form in offices).
🗣 In spoken American English: 'This too is temporary' is its comfort use — storms and jobs alike.
Register: Formal — time essential.
permanent /ˈpɜːrmənənt/ adjective C1 Time
Meaning: Lasting forever or for a very long time without changing; (of jobs) with no fixed end, unlike temporary work.
Example: She got a permanent job.
Another example: The ink leaves a permanent mark.
Collocations: a permanent job · permanent damage · permanent home
Synonyms: lasting, fixed, eternal
Antonyms: temporary, brief
Word family: permanently (adv) · permanence (n)
⚠ Common mistake: Its markers and jobs promise forever; its opposites staff summers. Hair salons sell 'perms' (permanent waves) — the adjective as a noun in beauty form.
🗣 In spoken American English: 'Permanent record' is school mythology's scariest file.
Register: Formal — time essential.
duration /djʊəˈreɪʃən/ noun C1 Time
Meaning: The length of time that something continues or lasts.
Example: The flight has a duration of three hours.
Another example: Stay for the duration of the course.
Collocations: the duration of · duration of the flight · short duration
Synonyms: length, span, time
Word family: durations (n pl) · during (prep — different word)
⚠ Common mistake: Form-filling's formal word for 'how long'. 'For the duration' means until the end — wartime British made it a byword for patience.
🗣 In spoken American English: Don't confuse with DURING (the preposition): duration is a noun only.
Register: Formal — time essential.
Practice — Time, Eras & Change
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