c. 1300, "to recite or cast a magic spell," from Old French charmer (13c.) "to enchant, to fill (someone) with desire (for something); to protect, cure, treat; to maltreat, harm," from Late Latin carminare, from Latin carmen "song, verse, enchantment, religious formula" (see charm (n.)). In Old French used alike of magical and non-magical activity. In English, "to win over by treating pleasingly, delight" from mid-15c.; weaker sense of "be highly pleasing" is by early 18c. Charmed (short for I am charmed) as a conventional reply to a greeting or meeting is attested by 1825.
"physician" (obsolete, poetical, or archaic), from Old English læce "leech," probably from Old Danish læke, from Proto-Germanic *lekjaz "enchanter, one who speaks magic words; healer, physician" (source also of Old Frisian letza, Old Saxon laki, Old Norse læknir, Old High German lahhi, Gothic lekeis "physician"), literally "one who counsels," perhaps connected with a root found in Celtic (compare Irish liaig "charmer, exorcist, physician") and Slavic (compare Serbo-Croatian lijekar, Polish lekarz), from PIE *lep-agi "conjurer," from root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')."
For sense development, compare Old Church Slavonic baliji "doctor," originally "conjurer," related to Serbo-Croatian bajati "enchant, conjure;" Old Church Slavonic vrači, Russian vrač "doctor," related to Serbo-Croatian vrač "sorcerer, fortune-teller." The form merged with leech (n.1) in Middle English, apparently by folk etymology. In early Middle English the word also was used of God and Christ; but by 17c. the sense had so deteriorated that leech typically was applied only to veterinary practitioners, and soon it was entirely archaic.
The fourth finger of the hand, in Old English, was læcfinger, translating Latin digitus medicus, Greek daktylus iatrikos, supposedly because a vein from that finger stretches straight to the heart.