(usually of relative importance, of degree, quantity or measure) In a double manner; with twice the severity or degree. / In two ways / (obsolete) with duplicity

(arithmetic) Leaving no remainder when divided by 4; divisible by 4.

(physics, of a transuranic nuclide) Having filled shells of both protons and neutrons and therefore having extra stability and a longer half-life than normal.

Both urinarily and faecally incontinent; having double incontinence.

(programming, of a data structure) Whose elements each link to the previous and the next element.

(mathematics) biinfinite

(linguistics) Synonym of ditransitive

(chemistry, American spelling) Water where both the hydrogen and oxygen atoms have been replaced by less common isotopes.