molecule

The smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms; a group of like or different atoms held together by chemical forces.

A small particle; a tiny bit.

The smallest mass of any substance which is capable of existing in a separate form — that is, the smallest part into which the substance can be divided without destroying its chemical character (identity).

A very small particle or bit of something; a particle; an atom.

In ornithology, the tread or cicatricula of a fecundated ovum.

One of the very small invisible particles of which all ordinary matter is supposed to consist.

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.

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. Cf. Atom.

The smallest particle of a specific element or compound that retains the chemical properties of that element or compound; two or more atoms held together by chemical bonds.