"to allot," Old English metan (West Saxon mæton), "to measure, ascertain the dimension or quantity of; measure out; compare; estimate the greatness of value of" (class V strong verb; past tense mæt, past participle meten), from Proto-Germanic *metana "to measure" (source also of Old Saxon metan, Old Frisian, Old Norse meta, Dutch meten, Old High German mezzan, German messen, Gothic mitan "to measure"), from PIE root *med- "take appropriate measures." Meaning "distribute or apportion by measure" is from c. 1300 and is the surviving sense, used now exclusively with out. Related: Meted; meting.

"consisting of five metrical feet," 1540s, from French pentametre, from Latin pentameter, from Greek pentametros (adj.) "having five measures," from pente "five" (see five) + metron "measure" (see meter (n.1)).

As a noun from 1580s, "a verse line of five feet;" in ancient prosody "a dactylic dipenthemimeres or combination of two catalectic dactylic tripodies" [Century Dictionary]. Saintsbury, the great early 20c. prosodist, objects to the "verse line" sense as a misuse of meter and prefers decasyllable.

in modern English prosody, a verse line of four feet, four beats, four accents, or eight natural iambics, depending how you hear it; 1610s, from Late Latin tetrametrus, from Greek tetrametron "verse of four measures" (generally trochaic), noun use of neuter of tetrametros (adj.) "having four measures," from tetra- "four" (from PIE root *kwetwer- "four") + metron "poetic meter, measure" (see meter (n.1)).

The English tetrameter line is not the classical one and seems to be native to the northern European languages. Saintsbury, the great early 20c. prosodist, objects to the "verse line" sense as a misuse of meter and prefers octosyllable though it begs the question of what is being counted.

also centimetre, metric measure of length, "one hundredth of a meter," 1801, from French centimètre (18c.), coined from Latin centum "hundred" (see hundred) + French mètre (see meter (n.2)).

"measure of length equal to the tenth part of a meter, 1809, from deci- + meter (n.2).

1540s, from Latin hexameter, from Greek hexametros "of six measures, composed of six feet; hexameter," from hex "six" (see six) + metron "poetic meter" (see meter (n.1)). As a noun, "a verse consisting of six measures," from 1570s. Chaucer has the word as exametron. Related: Hexametric.

1670s, from hydro- + meter (n.3). Related: Hydrometric; hydrometry.

also kilometre, "one thousand meters," by 1799 in translations from French, from French kilomètre (1795); see kilo- + meter (n.2). Related: Kilometric.

1570s, "insert (a name) in a register or official list," especially "to admit (a student) to a college by enrolling his name on the register," from Late Latin matriculatus, past participle of matriculare "to register," from Latin mātricula "public register," diminutive of mātrix (genitive mātricis) "list, roll," also "sources, womb" (see matrix).

The connection of senses in the Latin word seems to be via confusion of Greek mētra "womb" (from mētēr "mother;" see mother (n.1)) and an identical but different Greek word mētra meaning "register, lot" (see meter (n.2)). Evidently Latin mātrix was used to translate both, though it originally shared meaning with only one.

Intransitive sense of "to be entered as a member of a university or college, to become a member of a body or society" is by 1851. Also from late 16c. in English as "to adopt as a child; to naturalize," from the other sense of the Latin word, but these meanings now are obsolete. A list or register of persons belonging to an order, society, etc. was a matricula (1550s), from a diminutive of Latin mātrix. Related: Matriculated; matriculating.

chiefly British English spelling of meter (n.); for spelling, see -re.