molar (adj.) Look up molar at Dictionary.com
in chemistry, "pertaining to one mole," 1902, from mole (4) + -ar.
molar (n.) Look up molar at Dictionary.com
"grinding tooth," mid-14c., from Latin molaris dens "grinding tooth," from mola "millstone," from PIE root *mel- "to rub, grind" (see mill (n.1)). As an adjective in this sense from 1620s. In Old English they were cweornteð "quern-teeth."