sīdus
sīdus uit.-lat.
Tentatively thought to derive from a Proto-Italic *sīþos (“mark, target”), with a putative semantic shift (from hunters' jargon) from "target" > "star". Further origin unclear, with multiple theories proposed:[1]
- Some derive this from Proto-Indo-European *sweyd- (“sweat”), whence Latin sūdor, Ancient Greek ἱδρώς (hidrṓs), English sweat; however there are phonetic problems, most notably the initial /s/in Greek instead of expected */h/.
- Rix, connecting the word to Ancient Greek ῑ̓θῠ́ς (īthús, “straight, just”) and Sanskrit साध् (sādh, “to go straight to a goal”), derives the terms from a Proto-Indo-European *seHdʰ- (“to achieve a goal”), and the Latin from a reduplicative form *si-sHdʰ-u- > *sisdʰu- > *sizdu- > *sīdu-. This is semantically tenuous.
- Compare Ancient Greek σίδηρος (sídēros, “iron”). This is semantically unconvincing.
- Possibly borrowed from a substrate.
- Perhaps from a Proto-Indo-European *sh₂i-dʰh₁-o- (“binding”), from *sh₂ey- (“to bind, tie, fasten”), whence saeculum (“age, race, generation”). De Vaan tentatively prefers this derivation.
- (Classical Latin) IPA(key): /ˈsiː.dus/, [ˈs̠iːd̪ʊs̠]
- (modern Italianate Ecclesiastical) IPA(key): /ˈsi.dus/, [ˈsiːd̪us]
sīdus n (genitive sīderis); third declension
- group of stars, constellation, asterism [ quotations ▼]
- a star [ synonyms ▲]
- (poetic) the night sky
- (figuratively) a season (of the year)
Third-declension noun (neuter, imparisyllabic non-i-stem).
| Case | Singular | Plural |
|---|---|---|
| Nominative | sīdus | sīdera |
| Genitive | sīderis | sīderum |
| Dative | sīderī | sīderibus |
| Accusative | sīdus | sīdera |
| Ablative | sīdere | sīderibus |
| Vocative | sīdus | sīdera |