Mom

google

ref

late 19th century: abbreviation of momma. Compare with mum1.

wiktionary

ref

Abbreviation of momma.

etymonline

ref

mom (n.)

"mother," 1867, American English, perhaps a shortening of mommy; also see mamma. Adjectival phrase mom and pop to indicate a small shop or other business run by a married couple is by 1946.