O.b.
abb. operated by, as used in keying schedules

occupancy type
adj. the use to which an area of a building is put with reference to the prevailing life safety or building code

odometer method
n. a means of populating the KBA as a counter from the TMK combination

Oe
abb. oersted

oersted
n. a unit of magnetic field strength which is commonly used in the magnetic recording industry

offset cam
n. a cam which is bent to have its ends in different planes

oil cup
n. a receptacle for lubricant on a machine

one bitted
adj. of or pertaining to a cylinder which is or is to be combinated to keys cut to the manufacturer's reference number one bitting

one column progression
n. a process wherein key bittings are obtained by using the cut possibilities in one column of the key bitting array

one pin master key
n. a master key for all combinations obtained by progressing only one bitting position

one shot
adj. of or pertaining to a wire run that has an unobstructed line of sight

one-way deadbolt
n. a deadbolt operable from only one side of a door

open back strike
n. a strike, typically used on double door applications, that has an unenclosed opening opposite the lip edge

open face dial
n. a combination lock actuator designed to have all the numbers visible at once

open gated
adj. pertaining to a lever tumbler whose gate is in the edge of the tumbler

open loop
n. a detection circuit where continuity between branches will result in a reportable condition

opening index
n. the index or mark to which a combination is dialed in order to effect an opening

operating key
n. any key which will properly operate a lock or cylinder to lock or unlock the lock mechanism and is not a control key or reset key, see also "change key"

operating shear line
n. any shear line which allows normal operation of a cylinder or lock

original key blank
n. a key blank supplied by the lock manufacturer to fit that manufacturer's specific product

out of time
adj. of or pertaining to a condition where a mechanical part is misoriented and cannot function correctly

overhead concealed closer
n. a closer designed for installation out of view in the door header area

overhead stop
n. a door stop which contacts the door near the top

override code
n. in an electronic lock, a factory-set or user-set combination that will always open the lock

override combination
n. in certain locks with a user changeable combination, a second combination which allows access at all times. It is usually factory set and may not be field changeable.