Sole
Middle English: from Old French, from Latin solea ‘sandal, sill’, from solum ‘bottom, pavement, sole’; compare with Dutch zool and German Sohle .
wiktionary
From Middle English sole, soule, from Old French sol, soul(“alone”), from Latin sōlus(“alone, single, solitary, lonely”). Ultimately from Proto-Indo-European *swé(reflexive pronoun). Perhaps related to Old Latin sollus(“whole, complete”), from Proto-Indo-European *solw-, *salw-, *slōw-(“safe, healthy”). More at save.
From Middle English sole, soole, from Old English sole, solu. Reinforced by Anglo-Norman sole, Old French sole, from Vulgar Latin *sola(“bottom of the shoe”, also “flatfish”), from Latin solea(“sandal, bottom of the shoe”), from Proto-Indo-European *swol-(“sole”). Cognate with Dutch zool(“sole, tread”), German Sohle(“sole, insole, bottom, floor”), Danish sål(“sole”), Icelandic sóli(“sole, outsole”), Gothic 𐍃𐌿𐌻𐌾𐌰( sulja, “sandal”). Related to Latin solum(“bottom, ground, soil”). More at soil.
From Middle English sole, soole, from Old English sāl(“a rope, cord, line, bond, rein, door-hinge, necklace, collar”), from Proto-Germanic *sailą, *sailaz(“rope, cable”), *sailō(“noose, rein, bondage”), from Proto-Indo-European *sey-(“to tie to, tie together”). Cognate with Scots sale, saile(“halter, collar”), Dutch zeel(“rope, cord, strap”), German Seil(“rope, cable, wire”), Icelandic seil(“a string, line”). Non-Germanic cognates include Albanian dell(“sinew, vein”).
From Middle English sol, from Old English sol(“mire, miry place”), from Proto-Germanic *sulą(“mire, wallow, mud”), from Proto-Indo-European *sūl-(“thick liquid”). Cognate with Saterland Frisian soal(“ditch”), Dutch sol(“water and mud filled pit”), German Suhle(“mire, wallow”), Norwegian saula, søyla(“mud puddle”). More at soil.
From earlier sowle(“to pull by the ear”). Origin unknown. Perhaps from sow(“female pig”) + -le, as in the phrase "take a sow by the wrong ear", or from Middle English sole(“rope”). See above.
etymonline
sole (n.1)
"bottom of the foot" ("technically, the planta, corresponding to the palm of the hand," Century Dictionary), early 14c., from Old French sole, from Vulgar Latin *sola, from Latin solea "sandal, bottom of a shoe; a flatfish," from solum "bottom, ground, foundation, lowest point of a thing" (hence "sole of the foot"), a word of uncertain origin. In English, the meaning "bottom of a shoe or boot" is from late 14c.
sole (adj.)
"single, alone, having no husband or wife; one and only, singular, unique," late 14c., from Old French soul "only, alone, just," from Latin solus "alone, only, single, sole; forsaken; extraordinary," of unknown origin, perhaps related to se "oneself," from PIE reflexive root *swo- (see so).
sole (n.2)
common European flatfish, mid-13c., from Old French sole, from Latin solea "a kind of flatfish," originally "sandal" (see sole (n.1)); so called from resemblance of the fish to a flat shoe.
sole (v.)
"furnish (a shoe) with a sole," 1560s, from sole (n.1). Related: Soled; soling.
