Definition of "per"
To each, in each (used in expressing ratios of units).
Via (the), by (the), through (the) (followed by Latin name for an orifice).
In accordance with.
They (singular). Gender-neutral third-person singular subject pronoun, coordinate with gendered pronouns he and she.
Them (singular) Gender-neutral third-person singular object pronoun, grammatically equivalent to the gendered him and her.
Belonging to per, their (singular). Gender-neutral third-person singular possessive adjective, coordinate with gendered his and her.