See also: Appendix:Variations of "od"
- O.D. (Doctor of Optometry)
- Abbreviation of overdose.
- (professional degree) Doctor of Optometry
- Abbreviation of overdrive.
- Abbreviation of overdraft.
- Initialism of optical density.
- (of a pipe or tube) Initialism of outer diameter.
- (Australia, on road signs) Initialism of over dimension, used on route numbers for large vehicles, and normally followed by a numeral, eg. OD5.
- (management) Initialism of Organization development.