Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
oc-căno (obc-), ui, 3, v. n., milit., to blow. sound a wind instrument (very rare; not in Cic. or Cæs.): cornicines occanuere, Sall. Fragm. ap. Diom. p. 370 P. (Hist. 1, 71): tum Sentius occanere cornua jussit, Tac. A. 2, 81; v. occino.