Entries linking to severally
early 15c., "existing apart," from Anglo-French several, from Old French seperalis "separate," from Medieval Latin separalis, from Latin separ "separate, different," 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"). Meaning "various, diverse, different" is attested from c. 1500; that of "more than one" is from 1530s, originally in legal use. Related: Severalty. Jocular ordinal form severalth attested from 1902 in American English dialect (see -th (2)).
Here we are all, by day; by night we're hurled
By dreams, each one into a several world
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.