/mol"euh kyoohl'/ , n.
1. Chem. , Physics. the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound.
2. Chem. a quantity of a substance, the weight of which, measured in any chosen unit, is numerically equal to the molecular weight; gram molecule.
3. any very small particle.
[ 1785-95; earlier molecula mole ( s ) mass + -cula -CULE 1 ]