Correct spelling for the English word "gonus" is [ɡˈə͡ʊnəs], [ɡˈəʊnəs], [ɡ_ˈəʊ_n_ə_s] (IPA phonetic alphabet).
In bot., words which signify, when the latter part of a compound, either "kneed" or "angled,"-as polygonum, many-kneed; tetragonum, four-angled.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.