mola (n.1)

"large, clumsy type of tropical fish, sunfish," 1670s, from Latin mola, literally "millstone" (from PIE root *mele- "to crush, grind"). So called because of the fish's shape and rough skin. Attested in nativized form mole from c. 1600.

also mole (late 14c.), "false conception; shapeless, compacy, fleshy mass in the uterus," from Latin mola "false conception," from earlier sense "salt cake;" literally "millstone" (from PIE root *mele- "to crush, grind"). The Latin form is attested in English from c. 1600.