(informal, computing) A programmer who works only on open source programs.

(clothing) Open at the neck.

(transitive, simile) Alternative form of read like a book

(programming, informal) A binary operator that returns its first operand if that operand evaluates to true, and otherwise evaluates and returns its second operand.

(geometry, differential geometry) The differential of the Gauss map of an oriented surface at a given point on the surface.

(military) A military unit formed up so as to allow space between its ranks. / (nautical) A naval formation in which ships are four cables'-length (2880 feet) apart.

plural of open tuning

(music) A tuning of a guitar or other stringed instrument in which the strings sound a chord when strummed together without being pressed against the fretboard.

(mechanics) A type of differential gear used in automobile construction, allowing for output shafts to have different angular velocity, while equalizing torque applied to each output shaft.

(surgery) A surgical operation on the heart while a machine keeps the blood flowing.