solidly or securely fixed; stable

said of a surface or structure: not yielding to pressure; solid and compact

having a sustained strength

a firm grip

said of an opinion or principle: unchanging; steadfast

said of friends: having a strong and constant relationship

said of a decision or arrangement: settled or definite

said of a currency, share price, etc: not fluctuating in value; steady or more likely to rise than fall

said of evidence: well-founded

resolute in dealing with people or situations

said of the chin, jaw, or mouth: determined-looking

to make (something) solid, compact, firm, or secure

Then firm the soil round the plant

He firmed his grip on the racket

(also + up) to settle (an agreement, arrangement, etc) or put it into final form

firm a contract

firm up one's plans

to give additional support to or strengthen (a currency, or the price of a commodity or stock)

A lively stock market helped to firm the pound

said of prices or a market: to recover from a decline; to improve

At close of trading the market had firmed slightly

a business partnership of two or more people

any business unit or enterprise

a group of hospital doctors usu under a particular consultant

(usu The Firm) a criminal gang or an organized group of troublemakers, esp football supporters who look for fights