"relating to or consisting of molecules," by 1815, from molecule + -ar or else from French moléculaire or Modern Latin molecularis. Molecular biology is attested by 1950.
Entries linking to molecular
molecule n.
1794, "extremely minute particle," from French molécule (1670s), from Modern Latin molecula, diminutive of Latin moles "mass, barrier" (see mole (n.3)). For ending see -cule. It has a vague meaning at first; the vogue for the word (used until late 18c. only in Latin form) can be traced to the philosophy of Descartes. First used of Modern Latin molecula in modern scientific sense ("smallest part into which a substance can be divided without destroying its chemical character") is by Amedeo Avogadro (1811).
-ar
word-formation element meaning "pertaining to, of the nature of," from Latin -arem, -aris "of the kind of, belonging to," a secondary form (by dissimilation) of -alis, used after syllables with an -l- (such as insularis for *insulalis, stellaris for *stellalis).