Me a few months ago: "I need to take a PTO day tomorrow."
Boss: "What for?"
Me: "It's P."
She never asked again.
Boss: "What for?"
Me: "It's P."
She never asked again.
(I'm guessing you mean Private Time Off?)
Basically paternity / maternity leave, sick leave, vacation, jury duty, bank holiday, or whatever else is in the company's PTO policy...
And I'm also in the U.S.
Confusingly, paid time off (with the same abbreviation) is also sometimes used in the more obvious sense encompassing all or most paid leave (including some or all of things like bereavement, company/public holidays, paid time for administrative shutdowns, etc.)
(All of this is in the U.S.)