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A shell is a payload-carrying projectile which, as opposed to shot, contains an explosive or other filling, though modern usage sometimes includes large solid projectiles properly termed shot (AP, APCR, APCNR, APDS, APFSDS and proof shot).〔http://www.thefreedictionary.com/shells〕 Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used. Originally it was called a "bombshell", but "shell" has come to be unambiguous in a military context. All explosive- and incendiary-filled projectiles, particularly for mortars, were originally called ''grenades'', derived from the pomegranate, whose seeds are similar to grains of powder. Words cognate with ''grenade'' are still used for an artillery or mortar projectile in some European languages. Shells are usually large-calibre projectiles fired by artillery and combat vehicles (including tanks), and warships. Shells usually have the shape of a cylinder topped by an ogive-shaped nose for good aerodynamic performance, possibly with a tapering base; but some specialized types are quite different. ==History== Solid cannonballs ("shot") did not need a fuse, but hollow munitions ("shells") filled with something such as gunpowder to fragment the ball, needed a fuse, either impact (percussion) or time. Percussion fuses with a spherical projectile presented a challenge because there was no way of ensuring that the impact mechanism hit the target. Therefore, shells needed a time fuse that was ignited before or during firing and burnt until the shell reached its target. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Shell (projectile)」の詳細全文を読む スポンサード リンク
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