Third-person singular simple present indicative form of open source

present participle of open source

plural of open cluster

(uncountable) A chess opening characterized by the moves 1.e4 e5, in which both White and Black move their king's pawn to the fourth rank with their first move.

Third-person singular simple present indicative form of open fire

plural of open game

(topology) A cover whose members are all open sets.

plural of pipe-opener

(education) Referring to exams in which external resources such as textbooks, glossaries, study notes, calculators, etc. may be used.

(idiomatic) Something of which salient aspects are obvious or easily interpreted.