Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
cēnātĭo (caen- and coen-), ōnis, f. [cena] (lit. an eating, dining), meton. (like cena, II. C.), a dining-room, a dining-hall (post-Aug. prose), Plin. Ep. 2, 17, 10 and 12; Plin. 36, 7, 12, § 60; Sen. Prov. 4, 9; id. Cons. ad Helv. 9, 2; id. Ep. 90, 9; 115, 8; id. Q. N. 4, 13, 7; Col. 1, 6, 2; Petr. 77, 4; Suet. Ner. 31 bis.; Juv. 7, 183; Mart. 2, 59, 1.