Per

1. For each.

   $2.50 per dozen

2. To each, in each (used in expressing ratios of units).

   100 centimeters per meter

3. By the, by means of the, via the, through the.

   Introduce the endoscope per nasum.

4. In accordance with.

   I parked my car at the curb per your request.

adjective

Belonging to per, their (singular). Gender-neutral third-person singular possessive adjective, coordinate with gendered his and her.

1. They (singular). Gender-neutral neologistic third-person singular subject pronoun, coordinate with gendered pronouns he and she.
2. Them (singular) Neologistic gender-neutral third-person singular object pronoun, suggested for use in place of him and her.