Af
- AF
- Abbreviation of Across Flats.
- Affine Cipher
- Affine ciphers use linear functions to scramble the letters of secret messages.
- Affine Space
- A geometric structure that generalizes the affine properties of Euclidean space.
- Affinity
- Chemical attraction.
- AFR
- Abbreviation of Air-Fuel Ratio.
- Aft
- The back of a vessel.
- After Bottom Dead Centre
- The position of the piston as it starts its way up.
- After Image
- An image seen after the eye′s retina has been exposed for a time to an intense or stationary light source.
- Afterburner
- Thrust augmentation feature of a gas turbine engine.
- Afterheat
- The heat generated in a reactor core after shutdown by continuing radioactive decay of fission products.
- Aftermarket
- All products and services used in the repair and maintenance of vehicles after the vehicle has been sold.
- Aftertreatment
- Exhaust gas treatment after the combustion chamber, such as a catalyst.