Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† pĕtaurum, i, n., = πέταυρον, a stage or spring-board used by tumblers and rope-dancers, Lucil. ap. Fest. s. v. petauristae, p. 206 Müll.; Mart. 2, 86, 8; 11, 21, 3; Juv. 14, 265; Manil. 5, 434; Petr. Fragm. 13.