Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
concămĕrātĭo, ōnis, f. [concamero], a vaulting; a vault, Vitr. 2, 4; 5, 10; Plin. 11, 10, 10, § 22; Dig. 32, 31 al.