Definition of "greenbul"

We investigated the differences in environmental selection pressures between ecotone and rainforest that could have driven the song divergence in little greenbuls, in particular the divergence in Fmin (Slabbekoorn & Smith 2002b).

2005, T. B. Smith et al., “Putting process on the map”, in Andrew Purvis, John L. Gittleman, Thomas Brooks, editors, Conservation Biology 8: Phylogeny and Conservation, page 178

The commonest of the dull olive-green greenbuls, the Sombre Greenbul is most easily distinguished by its white eye; the race to the northeast is much yellower below and could readily be mistaken for a Yellow-bellied Greenbul were it not for its white eye.

2006, Ian Sinclair, Ian Davidson, Sasol Southern African Birds: A Photographic Guide, page 198

Birdwatchers based in Africa's savanna belt will generally want to focus more on forest birds, but mostly on such common and iconic species as great blue turaco or black-and-white casqued hornbill rather than on glimpsing a selection of more localised but duller forest greenbuls.

2013, Philip Briggs, Andrew Roberts, Uganda, 7th edition, Bradt Travel Guides, page 56