A soldier is a person who is a member of an army. A soldier can be a conscripted or volunteer enlisted person, a non-commissioned officer, a warrant officer, or an officer.

An army, ground force or land force is an armed force that fight primarily on land. In the broadest sense, it is the land-based military branch, service branch or armed service of a nation or country. It may also include aviation assets by possessing an army aviation component. Within a national military force, the word army may also mean a field army.