Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pondĕrātĭo, ōnis, f. [pondus], a weighing, poising (post-Aug.); plur., Vitr. 10, 3, 7: aequā ponderatione confici, Theod. Prisc. 1, 13; Vulg. Ecclus, 6, 15.