Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
* lectisternĭātor, ōris, m. [lectisternium], one who arranged the couches and placed the cushions on them for reclining on at table: propera, abi intro; tu esto lectisterniator, Plaut. Ps. 1, 2, 29; cf.: lectis sternundis studuimus, id. Stich. 5, 3, 5.