Very close to, but not quite. / (mathematics) Up to, except for a negligible set (where negligible is not universally but contextually defined).

(informal) Something or someone that doesn't quite make it.

plural of almost

The quality of almost being something, or almost reaching a point; incomplete state.

(measure theory) For all elements except those contained in some set of measure zero. / Used other than figuratively or idiomatically: see almost, everywhere.

(mathematics) All, except for a negligible set, i.e. finite, countable or of measure zero. / Used other than figuratively or idiomatically: see almost, all.

(probability theory) With probability equal to one.

plural of almost prime

(number theory) A natural number for which there exists an absolute constant K such that the number has at most K prime factors.

(number theory) Having this property.