Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pulvīnāris, e, adj. [pulvinus], of or belonging to a cushion or pillow: pica, sitting on a cushion, Petr. 37.
pulvīnārĭum, ĭi, n.
* pulvīnārĭus, a, um, adj. [pulvinar], of or belonging to the couches of the gods: macellum pingue pulvinarium, i. e. provision of beasts for sacrifice, Prud. στεφ 10, 1056 (yet pulvinarium is perh. gen. plur. of pulvinar).