APPORTIONMENT (Fr. _apportionement;_ Med. Lat. _apportionamentum;_ derived from Lat. portio, share), distribution or allotment in proper shares; a term used in law in a variety of senses, (1) Sometimes it is employed roughly and with no technical meaning to indicate 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). (2) In its strict legal interpretation apportionment falls into two classes, "apportionment in respect of estate" and "apportionment in respect of time."
1. _Apportionment in respect of Estate_ may result either from the act of the parties or from the operation of law. Where a lessee is evicted from, or surrenders or forfeits possession of part of the property leased to him, he becomes liable at common law to pay only a rent apportioned to the value of the interest which he still retains. So where the person entitled to the reversion of an estate assigns part of it, the right to an apportioned part of the rent incident to the whole reversion passes to his assignee. The lessee is not bound, however, by an apportionment of rent made upon the grant of part of the reversion unless it is made either with his consent or by the verdict of a jury. The assignee of the reversion of part of demised premises could not, at common law, re-enter for breach of a condition, inasmuch as a condition of re-entry in a lease could not at common law be apportioned. But this has now been altered by statute both in England (Law of Property Amendment Act 1859, § 3; Conveyancing Act 1881, § 12) and in many of the British colonies (e.g. Ontario, Rev. Stats., 1897, c. 170, § 9; Barbados, No. 12 of 1891, § 9). In the cases just mentioned there is apportionment in respect of estate by act of the parties.
_Apportionment by operation of law_ may be brought about where by act of law a lease becomes inoperative as regards its subject-matter, or by the "act of God" (as, for instance, where part of an estate is submerged by the encroachments of the sea). To the same category belongs the apportionment of rent which takes place under various statutes (e.g. the Lands Clauses Consolidation Act 1845, § 119, when land is required for public purposes; the Agricultural Holdings Act 1883, § 41, in the case of a tenant from year to year receiving notice to quit part of a holding; and the Irish Land Act 1903, § 61, apportionment of quit and crown rents).