notary n.

c. 1300, "a song, music, melody; instrumental music; a bird-song; a musical note of a definite pitch," from Old French note and directly from Latin nota "letter, character, note," originally "a mark, sign, means of recognition," which traditionally has been connected to notus, past participle of noscere "to come to know," but de Vaan reports this is "impossible," and with no attractive alternative explanation, it is of unknown origin.

Meaning "notice, attention" is from early 14c.; that of "reputation, fame" is from late 14c. From late 14c. as "mark, sign, or token by which a thing may be known." From late 14c. as "a sign by which a musical tone is represented to the eye." Meaning "a brief written abstract of facts" is from 1540s; meaning "a short, informal written communication" is from 1590s. From 1550s as "a mark in the margin of a book calling attention to something in the text," hence "a statement subsidiary to the text adding or elucidating something." From 1680s as "a paper acknowledging a debts, etc." In perfumery, "a basic component of a fragrance which gives it its character," by 1905.

"have (a document) legalized by a notary," 1930 (implied in notarized), from notary + -ize. Related: Notarizing.

also protonotary (under which spelling it appears in OED print edition), mid-15c., "principal clerk of a court," from Medieval Latin prothonotarius, from a Late Latin borrowing of Greek prōtonotarios "first scribe," originally the recorder of the court of the Byzantine empire, from prōtos "first" (see proto-) + Latin notarius (see notary). Related: Prothonotarial.

The -h- appeared in Medieval Latin, perhaps because Greek prōto- sometimes became prōth- (before an aspirated vowel); it was carried into Old French, which passed it to Middle English. Other Middle English proto- words from French also had variants in protho- (prothomartir "earliest martyr," Protheus "the god Proteus," prothogol "protocol," all 15c.), but soon it was purged from the others; prothonotary kept its perhaps through the powerful and necessary conservatism of legal language.