look up any word, like fleek:
a daily allowance, a daily fee

An employee can claim $120 per diem for 2 weeks towards food expenses.
by Balaji D August 27, 2006
Money that your employer grants you will traveling so you can drink alcohol liberally. Employer's province this entitlement to relieve stress derived from travel, bosses, co-workers, etc.
Going out of town sucks, by at least I can drink $40 of per diem to make up for it.
by rizzoyo June 28, 2014