mono-

mono- or mon-

pref.

1. One; single; alone: monomorphic.

2. Containing a single atom, radical, or group: monobasic.

3. Monomolecular; monatomic: monolayer.

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[Middle English, from Old French, from Latin, from Greek, from monos, single, alone; see men-⁴ in Indo-European roots.]

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mono- or before a vowel mon-

combining form

1. one; single: monorail, monolingual

2. Chem indicating that a chemical compound contains a single specified atom or group: monoxide [Greek monos alone]

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mono-

A prefix that means "one, only, single," as in monochromatic, having only one color. It is often found in chemical names where it means "containing just one" of the specified atom or group, as in carbon monoxide, which is carbon attached to a single oxygen atom.