1550s, "a sudden rush (out), a dashing or springing forth," especially of troops, from a besieged place, attacking the besiegers, from French saillie "a rushing forth," noun use of fem. past participle of saillir "to leap," from Latin salire "to leap" (see salient (adj.)).
Hence figuratively, in 17c. of spiritual matters, in 18c. of wit, etc. In architecture, "a projection," 1660s. Sally-port "gate or passage in a fortification to afford free egress to troops in making a sally" is from 1640s (with port (n.2)).
fem. proper name, an alteration of Sarah (compare Hal from Harry, Moll from Mary, etc.). Sally Lunn cakes (by 1780), sweet and spongy, supposedly were named for the young woman in Bath who first made them and sold them in the streets. Sally Ann as a nickname for Salvation Army is recorded from 1927.
of a troop or troops, "issue suddenly from a place of defense for the purpose of attack," 1540s, from sally (n.). Related: Sallied; sallying.
1570s, "a deviation in argument," also "a military sally," from Latin excursionem (nominative excursio) "a running forth, sally, excursion, expedition," figuratively "an outset, opening," noun of action from past-participle stem of excurrere "run out, run forth, hasten forward; project, extend," from ex "out" (see ex-) + currere "to run" (from PIE root *kers- "to run"). Sense of "journey" recorded in English by 1660s.
1640s, "a forerunner" (a sense now obsolete); by 1834 in pathology, "a prodromal symptom;" from French prodrome (16c.) and directly from Modern Latin prodromus, from Greek prodromos "a running forward, a sally, sudden attack," from pro "forward" (see pro-) + dromos "a running" (see dromedary). Related: Prodromata; prodromatic; prodromic; prodromous.
mid-14c., of water, etc., "to flow out;" of persons, "come or go (out of a place), sally forth," from issue (n.) or else from Old French issu, past participle of issir. Transitive sense of "to send out" is from mid-15c.; specific sense of "to send out authoritatively" is from c. 1600. Meaning "supply (someone with something)" is from 1925. Related: Issued; issuing.
1550s, Doll, an endearing name for a female pet or a mistress, from the familiar form of the fem. proper name Dorothy (q.v.). The -l- for -r- substitution in nicknames is common in English: compare Hal for Harold, Moll for Mary, Sally for Sarah, etc.
From 1610s in old slang in a general sense of "sweetheart, mistress, paramour;" by 1640s it had degenerated to "slattern." Sense of "a child's toy baby" is by 1700. Transferred back to living beings by 1778 in the sense of "pretty, silly woman." By mid-20c. it had come full circle and was used again in slang as an endearing or patronizing name for a young woman.