tetravus Save DMLBS tetravus [tetra+CL avus], (in list of words deriv. from avus) (great-)great-great-great-great-grandfather. avus componitur proavus ‥ abavus ‥ attavus ‥ tritavus, ‥ ~us, quartus ab avo, quod est ultimum cognationis nomen Osb. Glouc. Deriv. 21.