A reader asked why we call a group of lawyers who practise together a firm.
The term goes back a while.
In Italian, firma has been used since the sixteenth century to describe a commercial enterprise or business; the word also means ‘a signature’. Firmar and firmare (in Spanish and Italian, respectively) have meant ’to sign a document’ since the tenth century. All are derived from the post-classical Latin firmare (’to sign or ratify’).
English borrowed firm in the signature sense by the 1570s. By the eighteenth century, it had come to mean, by extension, the name under which a commercial enterprise transacts business, and also an association of two or more people in business together — what we would now call a partnership. Over time, it came to mean any kind of business or company, although for lawyers the partnership aspect has remained.
Since the early twentieth century, The Firm has been a colloquial term for the Royal Family; and since the 1950s for MI6, the British foreign intelligence agency.
The adjective firm, meaning ‘solid or steady’ (as in a firm offer or firm handshake) comes from a related Latin root: firmus (‘firm, solid or stable’).
One needs a steady hand when signing on behalf of a law partnership.