part of speech: preposition
definition 1: on or in the location of.
- We played volleyball at the beach.
definition 2: on or upon the occurrence of; during the time of.
- She moved to the city at the end of the year.
definition 3: in the direction of; toward.
- Look at the moon.
definition 4: engaged in the action of.
- Don’t disturb him when he’s at work.
definition 5: concerning; about.
- We were all excited at the possibility of winning first prize.