lemon [ME] The root of lemon and also lime [M17th] is an Arabic word, lim, that was a collective term for citrus fruit. On fruit machines the lemon is the least valuable symbol, and this may be behind the answer is a lemon [E20th] ‘the response or outcome is unsatisfactory’. Especially in the USA, a lemon may be a substandard or defective car, of the type all too often bought from shady used-car dealers.