Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
con-cēnātĭo (-caen-,-coen-), ōnis, f., a supping together, companionship at table; transl. of σύνδειπνον (like compotatio of συμπόσιον), Cic. Sen. 13, 45; id. Fam. 9, 24, 3.