The Collaborative International Dictionary
Spinebill \Spine"bill`\, n. (Zo["o]l.) Any species of Australian birds of the genus Acanthorhynchus. They are related to the honey eaters.
Wiktionary
n. Any of the Australian birds of the genus ''Acanthorhynchus'', related to the honeyeaters.
Wikipedia
Spinebill is the name given to two members of the honeyeater family, both in the genus Acanthorhynchus, which is Latin for "spine bill". They are around 15 centimetres in length, and are coloured black, white and chestnut, with a long, downcurved bill. They are native to Australia, with one species in the east and one in the west. They feed on nectar as well as insects, and live mainly in forests, gardens, and other shrubbery habitats.
A 2004 molecular study has shown that the two spinebills are a sister grouping to all other honeyeaters, that is, they diverged earlier than all other species.