Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
quā̆drĭflŭvĭum, ii, n. [quattuor-fluvius], a flowing into four parts, in four directions: ima abietis pars, cum excisa quadrifluviis disparatur, i. e. into four parts, according to the course of the veins, Vitr. 2, 9, 7.