Grenade
Historically, a grenade was a small explosive charge that could be thrown by hand. The hand grenade still exists but has evolved, but there are also a number of grenades fired by specialized launchers.
The most common filler for a grenade is explosive, sometimes broken into "offensive grenades" that do not scatter metal fragments, and the more common "defensive grenade" (or grenade without qualifier) that has a blast and fragmentation effect. Other fillers include colored smoke for signaling, white phosphorus for incendiary and screening smoke effect, thermite for incediary effect, illumination, and tear gas.
Hand grenade
Historic
World War I
World War II
Modern
Grenade launchers
Rifle grenade
Dedicated grenade launchers
The U.S. and many other countries use variants of 40mm grenades, fired from:
M-79
A weapon carried much like a large shotgun or tear gas gun, the M-79 breaks open at the breech to accept a single grenade. In addition to blast/fragmentation, smoke, white phosphorus, and illumination, it accepts a flechette made up of a bundle of darts for short-range antipersonel work. The other grenades must fly a minimum distance before they arm.
M-203
A single-shot launcher attachment for M16 rifle
Mark 19
A belt-fed full-automatic automatic grenade launcher, with versions that can be fired from a tripod, from a mount on a HMMWV or other vehicle, on river patrol boats, and helicopters.