Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
stīrĭcĭdĭum, ii, n. [stiria-cado], a falling of snow-flakes, a snowing: stiricidium quasi stillicidium, cum stillae concretae frigore cadunt. Stiria enim principale est, stilla deminutivum, Fest. p. 345 Müll.; so Cato ib. p. 344.