Another theory traces the Late Latin word to a metathesis of Latin vasculum. "The assumption that the word is of Teut[onic] origin is chronologically legitimate, and presents no difficulty exc[ept] the absence of any satisfactory etymology" [OED]. The similar words in Finnish and Slavic are held to be from Germanic.
It forms all or part of: accomplice; application; apply; complex; complexion; complicate; complication; complicity; deploy; display; duplex; duplicate; duplicity; employ; explicate; explicit; exploit; flax; implex; implicate; implication; implicit; imply; multiply; perplex; perplexity; plait; plash (v.2) "to interlace;" pleat; -plex; plexus; pliable; pliant; plie; plight (n.1) "condition or state;" ply (v.1) "work with, use;" ply (v.2) "to bend; ply (n.) "a layer, fold;" replica; replicate; replication; reply; simplex; splay; triplicate.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit prasna- "turban;" Greek plekein "to plait, braid, wind, twine," plektos "twisted;" Latin plicare "to lay, fold, twist," plectere (past participle plexus) "to plait, braid, intertwine;" Old Church Slavonic plesti "to braid, plait, twist," Russian plesti; Gothic flahta "braid;" Old Norse fletta, Old High German flehtan "to plait;" Old English fleax "cloth made with flax, linen."
late 14c., "flax prepared for spinning," also "refuse of flax used as kindling," somehow from the source of Old English lin "flax" (see linen). Perhaps from or by influence of French linette "grain of flax," diminutive of lin "flax," from Latin linum "flax, linen;" Klein suggests from Latin linteum "linen cloth," neuter of adjective linteus.
Later "flocculent flax refuse used as tinder or for dressing wounds" (c. 1400). Still used for "flax" in Scotland in Burns' time. Applied to stray cotton fluff from 1610s, though in later use this is said to be American English.
small finch-like Eurasian songbird, 1530s, from French linette "grain of flax," diminutive of lin "flax," from Latin linum "flax, linen thread" (see linen). Flaxseed forms much of the bird's diet. Old English name for the bird, linetwige, with second element perhaps meaning "to pluck," yielded Middle English and dialectal lintwhite. Also compare German Hänfling "linnet," from Hanf "hemp."
Woolen has begun the same evolution. Meaning "articles of linen fabric collectively" is from 1748, now sometimes extended unetymologically to cotton and artificial fabrics. The Old English noun also carried into Middle English as lin (n.) "linen" and persisted into 17c. and later in technical uses. The Middle English phrase under line (c. 1300) meant "in one's clothes." Linen-lifter (1650s) was old slang for an adulterous male.