'Molecule' definitions:

Definition of 'molecule'

From: WordNet
noun
(physics and chemistry) the simplest structural unit of an element or compound
noun
(nontechnical usage) a tiny piece of anything [syn: atom, molecule, particle, corpuscle, mote, speck]

Definition of 'Molecule'

From: GCIDE
  • Molecule \Mol"e*cule\, n. [Dim. fr. L. moles a mass: cf. F. mol['e]cule. See 3d Mole.]
  • 1. One of the very small invisible particles of which all ordinary matter is supposed to consist. [1913 Webster]
  • 2. (Physics) The smallest part of any substance which possesses the characteristic properties and qualities of that substance, and which can exist alone in a free state. [1913 Webster]
  • 3. (Chem.) A group of atoms so united and combined by chemical affinity that they form a complete, integrated whole, being the smallest portion of any particular compound that can exist in a free state; as, a molecule of water consists of two atoms of hydrogen and one of oxygen. Cf. Atom. [1913 Webster]

Synonyms of 'molecule'

From: Moby Thesaurus