Meaning of “past” - Learner’s Dictionary

past

adjective uk us /pɑːst/
BEFORE NOW [ always before noun ]

B1 having happened or existed before now:

I know this from past experience.
UNTIL NOW [ always before noun ]

B1 used to refer to a period of time before and until the present:

I've spent the past ten years in and out of jobs.
It's been raining for the past three days.
FINISHED [ never before noun ]

Something that is past has now finished:

My student days are past.
past tense

A2 the form of the verb that is used to show what happened in the past

(Definition of “past adjective” from the Cambridge Learner’s Dictionary © Cambridge University Press)