Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
hĭasco, ĕre, v. inch. n. [id.], to open, break open (ante- and post-class.): ubi primum nuces pineae incipiunt hiascere, Cato, R. R. 17, 2; Gargil. de Re Hort. 2, 1.