Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
partĭcĭpātĭo, ōnis, f. [participo], a sharing, partaking, participation (postclass.): imperii, Spart. Jul. 6 fin.; Aug. Quaest. 83, n. 24; Vulg. 1 Cor. 10, 16.