late 14c., mummie, "medicinal substance prepared from mummy tissue," from Medieval Latin mumia, from Arabic mumiyah "embalmed body," from Persian mumiya "asphalt," from mum "wax." Sense of "dead human body embalmed and dried after the manner of the ancient Egyptians" is recorded in English from 1610s. Mummy wheat (1842), grown in Egypt and Ethiopia and once thought to be a distinct species, was said to have been cultivated from grains found in mummy-cases.
Skelton was an early variant form. The noun use of Greek skeletos passed into Late Latin (sceletus), hence French squelette and rare English skelet (1560s), Spanish esqueleto, Italian scheletro. The meaning "bare outline" is first recorded c. 1600; hence skeleton crew (1778), skeleton key, etc. Phrase skeleton in the closet "source of secret shame to a person or family" is from 1812 (the image is perhaps from the Bluebeard fable).
late 14c., "study or knowledge of the structure and function of the human body" (learned by dissection); c. 1400, "anatomical structure," from Old French anatomie and directly from Late Latin anatomia, from late Greek anatomia for classical anatome "dissection," literally "a cutting up," from ana "up" (see ana-) + temnein "to cut" (from PIE root *tem- "to cut").
"Dissection" (1540s), "mummy" (1580s), and "skeleton" (1590s) were primary senses of this word in Shakespeare's day; meaning "the science of the structure of organized bodies" predominated from 17c. Of persons, "the body," from 1590s. Often misdivided as an atomy or a natomy (see N).
The scyence of the Nathomy is nedefull and necessarye to the Cyrurgyen 
"mother," a word used especially by children and infants, 1570s, representing the native form of the reduplication of *ma- that is nearly universal among the Indo-European languages (Greek mamme "mother, grandmother," Latin mamma, Persian mama, Russian and Lithuanian mama "mother," German Muhme "mother's sister," French maman, Welsh mam "mother").
Probably a natural sound in baby-talk, perhaps imitative of sound made while sucking. Its late appearance in English is curious, but Middle English had mome (mid-13c.) "an aunt; an old woman," also an affectionate term of address for an older woman.
In educated usage, the stress is always on the last syllable. In terms of the recorded appearance of the variant or related words in English, mama is from 1707, mum is from 1823, mummy in this sense from 1839, mommy 1844, momma 1810, and mom 1867. Mamma's boy "soft, effeminate male" is by 1901.