Adjective

1. Of that which comes before, in advance.

   I had no prior knowledge you were coming.

2. former, previous

   His prior residence was smaller than his current one.

Adverb

1. Previously.

   The had known three months prior.

Noun

1. A high-ranking member of a monastery, usually lower in rank than an abbot.
2. A previous criminal offense on someone's record.
3. In Bayesian inference, a prior probability distribution.