Proto-Indo-European root meaning "to rub off," also "to stroke; to milk," in reference to the hand motion involved in milking an animal. Compare *g(a)lag-.

It forms all or part of: emulgent; emulsify; emulsion; milch; milk.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit marjati "wipes off;" Greek amelgein, Latin mulgere, Old Church Slavonic mlesti, Lithuanian melžti "to milk;" Old Irish melg "milk."

liquid that remains after the butter has been churned out of milk, 1520s, from butter (n.) + milk (n.). Compare German Buttermilch, Dutch botermelk. 

before vowels, lac-, word-forming element used in chemistry and physiology from 19c. and meaning "milk," from Latin lac (genitive lactis) "milk," from Proto-Italic *(g)lagt-, from PIE root *g(a)lag- "milk." This and the separate root *melg- (source of milk (n.)) account for words for "milk" in most of the Indo-European languages. The absence of a common word for it is considered a mystery. Middle Irish lacht, Welsh llaeth "milk" are loan words from Latin.

"giving milk, having milk," late 13c., milche, melch, from Old English -milce "milking" (Anglian -melce, West Saxon -mielce), from Proto-Germanic *melik- "milk," from PIE root *melg- "to rub off; to milk." A variant form of milk. Since 18c. applied only to domestic animals and chiefly to cows. Milch-cow is from early 15c.

"woman who milks cows or is employed in a dairy," 1550s, from milk (n.) + maid.

"man who sells milk," especially one who goes door to door, 1580s, from milk (n.) + man (n.).

"A handsome and harmless serpent" [Century Dictionary], one of the larger snakes of the U.S., common in many states, by 1812, from milk (n.) + snake (n.). Also called chicken-snake (attested by 1793), house-snake, and thunder-and-lightning snake.

It [the milk-snake] sometimes in this county has been known to enter a grist-mill and remain a length of time for the apparent purpose of feeding on the mice which were there attainable. It is probable this is one principal object of his frequenting dwelling houses, and not always for the purpose of obtaining milk, as is generally supposed. [The American Journal of Science and Arts, April 1844]

term of contempt for an effeminate, spiritless man, "one who is devoid of manliness," late 14c.; attested as a (fictional) surname mid-13c.; also applied in Middle English to the infant Christ. Literal sense "piece of bread soaked in milk" attested late 15c.; see milk (n.) + sop (n.).

also milk-toast, 1831, "toast softened in milk," from milk (n.) + toast (n.1). Figurative of softness or innocence by 1859.

1590s, from milk (n.) + weed (n.); used in reference to various plants whose juice resembles milk.