- optical computing
- optical disk
- optical encoder
- optical image
- optical interface
- optical interference
- optical link
- optical modulator
- optical mouse
- optical neurocomputer
- optical processing
- optical radiation
- optical reader
- optical receiver
- optical recognition
- optical repeater
- optical scanner
- optical scanning
- optical storage
- obey
- obfuscate
- object
- object allocation
- object class
- object computer
- object deck
- object decomposition
- object file
- object identifier
- object language
- object map
- object modification
- object orientation
- object program
- object reuse
- object rights
- object table
- object tape
- object time
- object type
- object-action
- object-oriented
- oblate spheroid
- oblique
- oblique asteroid
- oblique cone
- oblique drawing
- oblique line
- oblique parallelepiped
- oblique pyramid
- oblique section
- oblong
- observe
- observed
- observed data
- obstruct
- obtainable
- obtuse angular
- obtuse triangle
- obverse
- occupancy problem
- octal
- octal digit
- octal number
- octode
- odd field
- oddity
- office data
- office typewriter
- official language
- offset stacker
- offset voltage
- OGC
- oil separator
- oil-bath
- old version
- omission
- omit
- omitted
- on memory
- optical transmission
- optical transmitter
- optimal
- optimal programming
- optimal recalculation
- optimal route
- optimal solution
- optimal strategy
- optimal trajectory
- optimality
- optimality principle
- optimization
- optimization control
- optimized code
- optimizer
- optimum allocation
- optimum code
- optimum coupling
- optimum programming
- optimum test