BACILLUS Meaning of BACILLUS in English [ bə'sɪləs ]■ noun ( plural bacilli -lʌɪ , -li: ) a rod-shaped bacterium.Derivativesbacillary adjective OriginC19: from late L. (genus name), dimin. of L. baculus 'stick'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004