A soldier is a general English term that refers to a member of a land component of national armed forces. In most societies of the world, "soldier" is also a general term for any member of the land forces including commissioned or non-commissioned officers.
The word soldier is derived from an Old French word, itself a derivation of Solidarius, Latin for someone who served in the armed forces for pay, as opposed to warriors in tribal society where every grown man is automatically a member of his clan's fighting force. Solidare in Latin means "to pay"; Roman soldiers were paid in solidi, so-called because they were a new type of solid silver coin brought in after a reform of the Roman monetary system.
In the Russian language the word soldier is also "солдат" ("soldat"), although it is not related to the Russian word for money, but was borrowed from German use. In some languages the word soldier is derived from different etymology, for example Estonian "sõdur" is derived from word "sõda," which means "war." And Finnish "sotilas" or "soturi", and "sota" meaning "war".
In most armed forces the word soldier has been mostly abandoned with increasing specialisation in military occupations that require different areas of knowledge and skill-sets, and have been replaced by names which reflect Arm, Service or Branch of individual's service, type of unit or operational employment or technical use such as: trooper, Commando, dragoon, infantryman, marine, paratrooper, ranger, sniper, engineer, sapper, or a gunner.