Meaning of DEFICIENCY in English
n. (pl. -ies) 1 the state or condition of being deficient. 2 (usu. foll. by of) a lack or shortage. 3 a thing lacking. 4 the amount by which a thing, esp. revenue, falls short. deficiency disease a disease caused by the lack of some essential or important element in the diet.
Concise Oxford English dictionary. Краткий оксфордский словарь английского языка. 2012