Thickhead \Thick"head`\, n.

1. A thick-headed or stupid person. [Colloq.]

2. (Zo["o]l.) Any one of several species of Australian singing birds of the genus Pachycephala. The males of some of the species are bright-colored. Some of the species are popularly called thrushes.

Source: Webster's Revised Unabridged Dictionary (1913)