- kbit One thousand bits of memory.
- Kevlar Aramid fibre used as basis of high-strength composites material.
- kg Kilogramme (2.20462 lb).
- kitbuilt Prefabricated aircraft for amateur assembly.
- KK Kabushiki Kaisha (Japanese company constitution).
- km/h Kilometres per hour.
- kN KiloNewtons (Nx10³). See N.
- knot 1 n mile per hour (1.852 km/h; 1.15078 mph).
- Krueger flap Hinges down and then forward from below the leading-edge.
- kVA Kilovolt-amperes.
- kW Kilowatt, SI measure of all forms of power (not just electrical).