高射炮(antiaircraft gun)
从地面或甲板上射击的抵御空袭的火炮（artillery）。第一次世界大战中首次使用，将野战炮改装成用於防空的炮，但是瞄准手段不够好。1920年代和1930年代，测距仪（range finder）、探照灯、定时引信和瞄准机构都有了巨大的发展。第二次世界大战中，出现了速射自动高射炮，雷达用於跟踪目标，小型无线电近炸引信在弹头接近目标时使之起爆。英、美军队广泛使用瑞典博福斯公司最先生产的40公厘高射炮来对付俯冲轰炸机和低空攻击机，它能将炮弹以120发／分的射速射至2哩（3.2公里）高。对付高空飞行的轰炸机的重型高炮的口径达到120公厘。高射炮中效果最好的是德国88公厘的高射炮（Fliegerabwehrkanone），它的缩略语flak成为防空火力的通用语。随着1950年代和1960年代间装备地对空导弹（guided missile），诸如此类的重型高炮便退役了，不过口径为20～40公厘的雷达制导的自动高炮仍然能有效地防御低空飞行的飞机和直升机。
English version：
antiaircraft gun
Artillery piece fired from the ground or shipboard in defense against aerial attack. They were first used in combat in World War I, when field artillery were converted to antiaircraft use by mountings that enabled them to fire nearly vertically. Range finders and searchlights, developed in the 1920s and '30s, increased their effectiveness. Advances in World War II included rapid-firing and automatic weapons, radar for target tracking, and radio-operated fuses. British and U.S. forces used a 40-mm gun that fired ammunition to a height of 2 mi (3.2 km). Heavier guns, up to 120 mm, were used against high-flying bombers. For most of the war, the most effective was the German 88-mm Fliegerabwehrkanone; its abbreviated name, flak, became a universal term for antiaircraft fire. With the introduction of guided missiles in the 1950s and '60s, heavy antiaircraft guns were phased out, though lighter radar-guided automatic guns remained effective against low-flying aircraft and helicopters.