The legal term apportionment (French: apportionement; Mediaeval Latin: apportionamentum, derived from Latin: portio, share), also called delimitation, is in general the distribution or allotment of proper shares, though may have different meanings in different contexts. Apportionment can refer to estate, the amount of compensation received by a worker and in respect of time.

This term may be employed roughly and sometimes has no technical meaning; this indicates the distribution of a benefit (e.g. salvage or damages under the Fatal Accidents Act 1846, § 2), or liability (e.g. general average contributions, or tithe rent-charge), or the incidence of a duty (e.g. obligations as to the maintenance of highways).