| sinornis | (n) sparrow-sized fossil bird of the Jurassic period to the Cretaceous period having a keeled breastbone and vestigial tail; found in China; considered possibly the second most primitive of all birds |
| genus sinornis | (n) a genus of fossil birds |
| genus sinornis | (n) a genus of fossil birds |
| sinornis | (n) sparrow-sized fossil bird of the Jurassic period to the Cretaceous period having a keeled breastbone and vestigial tail; found in China; considered possibly the second most primitive of all birds |