Entries linking to in-service
a Middle English merger of Old English in (prep.) "in, into, upon, on, at, among; about, during;" and Old English inne (adv.) "within, inside," from Proto-Germanic *in (source also of Old Frisian, Dutch, German, Gothic in, Old Norse i), from PIE root *en "in." The simpler form took on both senses in Middle English.
Sense distinction between in and on is from later Middle English, and nuances in use of in and at still distinguish British and American English (in school/at school). Sometimes in Middle English shortened to i.
The noun sense of "influence, access (to power or authorities)," as in have an in with, is first recorded 1929 in American English. to be in for it "certain to meet with something unpleasant" is from 1690s. To be in with "on friendly terms with" is from 1670s. Ins and outs "intricacies, complications of an action or course" is from 1660s. In-and-out (n.) "copulation" is attested from 1610s.
c. 1100, "celebration of public worship," from Old French servise "act of homage; servitude; service at table; Mass, church ceremony," from Latin servitium "slavery, condition of a slave, servitude," also "slaves collectively," from servus "slave" (see serve (v.)).
Meaning "act of serving, occupation of an attendant servant" is attested from c. 1200, as is that of "assistance, help; a helpful act." From c. 1300 as "provision of food; sequence of dishes served in a meal;" from late 14c. as "service at table, attendance during a meal." Meaning "the furniture of the table" (tea service, etc.) is from mid-15c.
Meanings "state of being bound to undertake tasks for someone or at someone's direction; labor performed or undertaken for another" are mid-13c. Sense of "service or employment in a court or administration" is from c. 1300, as is that of "military service (especially by a knight); employment as a soldier;" hence "the military as an occupation" (1706).
Also in Middle English "sexual intercourse, conjugal relations" (mid-15c.; service of Venus, or flesh's service). Service industry (as distinct from production) attested from 1938. A service station originally was a gas stop that also repaired cars.