(rare, mathematics, of a set) Being the interior of its closure.

A place of employment in which employment is in no way contingent on membership in a union, though a union may be the exclusive bargaining agent of the employees.

(religion) The practice of some Protestant churches to allow all people to take Communion, regardless of being members of the church or not.

(organic chemistry) Having carbon atoms arranged in a linear rather than cyclical chain.

(nonstandard) Alternative spelling of open mic

plural of open mike

plural of open mic

In an open-ended manner; indefinitely; freely.

plural of open file

(chess) A file with no pawns of either color on it.