Initialism of United Nations.

Alternative spelling of 'un

(added to adjectives or past participles) not / (added to nouns) absent; lacking; not; negative / (added to nouns) contrary to or contrasted against traditional norms; unconventional; alternative

(added to verbs to form verbs) do the opposite of, reverse (a specified action) / (added to nouns to form verbs) deprive of, release from, free from, remove from, extract from

Used to form temporary names of elements (such as unbiunium) whose existence has been predicted, and have not yet been given a trivial name. / Used to form large numbers as the first in the sequence.

(colloquial) One (a thing). / (colloquial, facetious or dialectal, Cornwall) One (a person).

(chemistry) Used in the theoretical systematic names of undiscovered chemical elements, standing for a 1 in the atomic number

A surname.

plural of un

Initialism of Unified numbering system.