In most armies use of the word "soldier" has taken on a more general meaning due to the increasing specialization of military occupations that require different areas of knowledge and skill-sets. As a result, "soldiers" are referred to by names or ranks which reflect an individual's military occupation specialty arm, service, or branch of military employment, their type of unit, or operational employment or technical use such as: trooper, tanker (a member of tank crew), commando, dragoon, infantryman, guardian, artilleryman, paratrooper, grenadier, ranger, sniper, engineer, sapper, craftsman, signaller, medic, or a gunner.