late 14c., registre, "public record book, private account book, an official written account regularly kept," from Old French registre (13c.) and directly from Medieval Latin registrum, regestrum, properly regestum, from Late Latin regesta "list, matters recorded," noun use of Latin regesta, neuter plural of regestus, past participle of regerere "to record; retort," literally "to carry back, bring back" from re- "back" (see re-) + gerere "carry, bear" (see gest).
With unetymological second -r- in Medieval Latin and Old French by influence of other Latin nouns in -istrum (French -istre). The word was also borrowed in Dutch, German, Swedish, Danish.
Some later senses seem to be influenced by association with unrelated Latin regere "to rule, to guide, to keep straight." Meaning in printing, "exact alignment of presswork" is from 1680s. Musical sense is from 1811, "compass or range of a voice or instrument," hence "series of tones of the same quality" (produced by a voice or instrument).
From mid-15c. as "a record-keeper, recorder;" sense of "device by which data is automatically recorded" is by 1830, from the verb.
late 14c., registren (transitive), "to record, enter in a listing," from Old French registrer "note down, include" (13c.) and directly from Medieval Latin registrare, from registrum (see register (n.1)). From c. 1400 as "to enroll (someone) in a listing."
Intransitive sense, of instruments, is from 1797; of persons and feelings, "make an impression," by 1901. Meaning "to enter one's name in a list" for some purpose (as a voter, as a guest at a hotel, etc.) is by 1848. Related: Registered; registering. Registered nurse attested from 1879.
1560s, "act of inserting or recording in a register," from French registration and directly from Medieval Latin registrationem (nominative registratio) "a registering," noun of action from past-participle stem of registrare, from registrum (see register (n.1)). In 16c.-17c. it birthed a back-formed verb registrate.
"one whose business is to write or keep a register," especially "official who acts as a secretary to a university;" 1670s, shortening of registrary (1540s, long obsolete except at Cambridge), from Medieval Latin registrarius "one who keeps a record" (related to register (n.1)). Earlier were registerer "recorder, historian" (late 15c.), registrer (late 14c.), from the verb.
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.