Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
crĕpĭtācŭlum, i, n. [crepito], a rattle, Quint. 9, 4, 66; Mart. 14, 54; Mart. Cap. 1, § 7; 9, §§ 909, 927.