[′līt ‚ant·ē′er‚kraft är‚til·ə·rē] (ordnance) Conventional antiaircraft artillery pieces, usually under 90-millimeter, the weight of which in a trailed mount, including on-carriage fire control, does not exceed 20,000 pounds (9000 kilograms); self-propelled versions are rated in the same category as the trailed version.