| Lettish | zil, zilgans | blue; silis et var. Jay, 290 |
| Lith. | ziloka | bluish |
| Lith. | ziloji | White Wagtail, 313 |
| Lith. | zilas | having grey hair |
| Lith. | zilvitis | willow |
| Prussian | zil | Mallard, 40 (blue mirror on wing) |
| Anc.Greek | thèlis | fresh, tender, feminin |
| Germ.reg. | seelenmeise | Blue Tit, 391 |
| Esp. | pájaro cele | Blue Tit, 391 |
| Galice | celobre | blue |
| Esp. | celage | light of the sky |
| R.Rom. | cil | sky |
| Alb. | qiell | sky |
| Ital. | cielo | sky |
| Hebr. | sheol | abode of the dead (Deut. XXXII: 22); a European borrowing |
| Roman. | cer | sky |
| Roman. | ceruliu | sky blue |
| Lat. | caeruleus | blue |
| Anc.Greek | kérylos | (borrowing) blue; Kingfisher, 267 |
| Alb. | qelqtë | glass-like, made of glas |
| Alb. | qelibar | amber |