firm [ME] Firm meaning ‘not yielding to pressure’ comes from Latin firmus, also the root of farm [ME], which originally meant a tax or rent. Firm meaning ‘a company or business’ has the same root, but the immediate origin is different. The Latin word had also given rise to Italian firma ‘confirmed by signature’, and in the late 16th century this was adopted into English to mean ‘an autograph or signature’. Over time it came to mean the name under which business was transacted by an organization [M18th], as in ‘trading under the firm of “Grant & Co.”’. Finally, in the late 18th century, firm became the term for a company.