noun, noun which may take the genitive case particle 'no', adverb
old days; the past; a long time ago
Refers to a time long before now, often nostalgically or in contrast with the present. Can be used as a noun, adverb, or with の to modify nouns.
Long ago, there was a big forest here.
Looking at old photos makes me feel nostalgic.
He is as energetic as ever, just like in the old days.
the past ten years; the past decade
Used as a unit of time, often in expressions like ひと昔 (about ten years) or ふた昔 (about twenty years). Not used alone in this sense.
See also: 二昔
A decade ago, smartphones were still rare.
That's a story from twenty years ago.
This festival has continued since long ago.
This area used to be farmland long ago.
I take a morning walk again, just like I used to long ago.
昔 is the common everyday word for the distant past, whereas 古 carries a more elevated, literary tone.
昔 refers broadly to 'the old days' or a distant past era, whereas かつて is used more narrowly to mark a specific past state or experience that has since changed.
数年前 pins the past down to a few years, whereas 昔 is much vaguer and can mean anything from years to centuries ago.
当時 pinpoints a specific era already under discussion, while 昔 is vaguer and just means 'long ago' in general.
old-fashioned way of thinking; conservative mindset · old-fashioned; traditional
old friend; familiar face from the past
way in the past; two decades ago; about twenty years ago
long ago; once upon a time
people of the past; ancients; previous generations
paleolagine lagomorph; Amami rabbit; red rock hare
old-fashioned; in ancient style
old person; old-fashioned person
old-fashioned; old-style
horseweed; Canadian fleabane
old-fashioned person; old-timer; old fogey
archiannelid of genus Saccocirrus; Saccocirrus major