term:

Per Diem

per diem adv

[Latin]
: by the day
: for each day [paid per diem]
adj 1 : based on use or service by the day [per diem compensation]
2 : paid or calculated by the day [per diem interest]
n 1 : a daily allowance [received a per diem for expenses]
2 : a daily fee [paid a per diem for maintenance of the equipment]

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.