(in a bird) a triangular plate formed of the fused caudal vertebrae, typically supporting the tail feathers.
- ‘The tail is shortened and fused to form a pygostyle which bears tail feathers (retrices).’
- ‘All birds, both fossil and modern, have reduced the tail to a mass of fused vertebrae termed the pygostyle.’
Late 19th century: from Greek pugē ‘rump’ + stulos ‘column’.
We take a look at several popular, though confusing, punctuation marks.