severally (adv.)

early 15c., "existing apart, independent, not together," a sense now obsolete, also "a small number of; particular, special;" from Anglo-French several, from Old French seperalis "separate," from Medieval Latin separalis "separable," from Latin separ "separate, different," a back-formation from separare "to pull apart," from se- "apart" (see secret (n.)) + parare "make ready, prepare" (from PIE root *pere- (1) "to produce, procure").

Compare Anglo-Latin severalis, a variant of separalis. The meaning "various, diverse, different" (as in went their several ways) is attested from c. 1500; that of "more than one" is from 1530s, growing out of legal meanings of the word, "belonging or assigned distributively to certain individuals" (mid-15c.), etc. Also used by mid-17c. as "a vague numeral" (OED), in which any notion of "different" appears to have been lost. Related: Severalty; severality; severalfold. Jocular ordinal form severalth is attested from 1902 in colloquial American English (see -th (2)).

HERE we are all, by day : By night w'are hurl'd

By dreames, each one, into a sev'rall world.

[Herrick, 1648]

common adverbial suffix, forming from adjectives adverbs signifying "in a manner denoted by" the adjective, Middle English, from Old English -lice, from Proto-Germanic *-liko- (cognates: Old Frisian -like, Old Saxon -liko, Dutch -lijk, Old High German -licho, German -lich, Old Norse -liga, Gothic -leiko); see -ly (1). Cognate with lich, and identical with like (adj.).

Weekley notes as "curious" that Germanic uses a word essentially meaning "body" for the adverbial formation, while Romanic uses one meaning "mind" (as in French constamment from Latin constanti mente). The modern English form emerged in late Middle English, probably from influence of Old Norse -liga.