Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dĕcŏrāmen, ĭnis, n. [decoro], ornament, decoration (in post-Aug. poetry): vittaque, majorum decoramen, Sil. 16, 269: fluvii decoramina villae, Aus. Idyll. 10, 320.