A period of history generally seen as occurring before the Middle Ages, that is, before the fall of the Roman Empire. Includes Ancient Egypt, Ancient Greece and Ancient Rome.
That which happened a long time ago and not worth discussing any more.
A grammatical form (often a verb form) that refers to an event, transaction, occurrence, or object that happened (or had happened), or existed, at some time before now (the applicable reference time).
A grammatical form (often a verb form) that is used in a conditional expression to refer to an event, transaction, occurrence, or object that is hypothetical and often counterfactual.