o
- Obbligato
- object-oriented programming
- Oblique motion
- OCR
- Octatonic
- octave
- Octave
- Octave displacement
- Octave equivalence
- ODBC
- OEM
- off-axis rejection
- offset
- ohm
- on-demand
- one-off
- One sheet
- one-third octave
- online
- ontology
- OOP
- op amp
- Open Database Connectivity
- Open position
- Open Systems Interconnection
- operating system
- operational amplifier
- operator
- optical character recognition
- optical disc
- optical fiber
- opto-electronics
- Opus
- Orange Book standard
- original equipment manufacturer
- Ornament
- OS
- oscillator
- OSI
- Ostinato
- outboard
- outline font
- out-point
- output
- Outro
- outtake
- Out takes
- overdub
- Overdub
- overlay
- overs
- oversample
- overscan
- Overtones