A hand grenade is any small bomb that can be thrown by hand. Hand grenades are classified into three categories: explosive grenades, chemical grenades, and gas grenades. Explosive grenades are the most commonly used in modern warfare, and are designed to detonate after impact or after a set amount of time. Chemical and gas grenades are designed not to explode, but to burn or release a gas.
Grenadiers were originally soldiers who specialized in throwing grenades.
The word 'grenade' derives from the French word for a "small explosive shell." Its first usage in English dates from the 1590s. Likely derived from Old French pomegrenate (influenced by Spanish granada), so called because the many-seeded fruit suggested the powder-filled, fragmenting bomb, or from similarity of shape.
Chemical and gas grenades include smoke grenades and incendiary grenades. Unlike explosive grenades, chemical and gas grenades are designed to burn or to release a gas, not to explode.
Smoke grenades are used as ground-to-ground or ground-to-air signalling devices, target or landing zone marking devices, and screening devices for unit movement. The body is a sheet-steel cylinder with emission holes in the top and bottom. These allow the smoke to be released when the grenade is ignited. Two main types exist, coloured smoke (for signaling) and screening smoke. In coloured smoke grenades, the filler consists of 250 to 350 grams of coloured smoke mixture (mostly potassium chlorate, lactose and a dye). Screening smoke grenades usually contain HC (hexachloroethane/zinc) smoke mixture or TA (terephthalic acid) smoke mixture. HC smoke is harmful to breathe, since it contains hydrochloric acid. Whilst not intended as a primary effect, these grenades can generate enough heat to scald or burn unprotected skin and the spent casing should not be touched until it has cooled.