According to Beekes, probably from Pre-Greek as there's no connection with other words.
The ι is short in some sources and long in others, thus:
or
σῑ̆ρός • (sī̆rós) m (genitive σῑ̆ροῦ); second declension
Case / # | Singular | Dual | Plural | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Nominative | ὁ σῑ̆ρός ho sī̆rós |
τὼ σῑ̆ρώ tṑ sī̆rṓ |
οἱ σῑ̆ροί hoi sī̆roí | ||||||||||
Genitive | τοῦ σῑ̆ροῦ toû sī̆roû |
τοῖν σῑ̆ροῖν toîn sī̆roîn |
τῶν σῑ̆ρῶν tôn sī̆rôn | ||||||||||
Dative | τῷ σῑ̆ρῷ tôi sī̆rôi |
τοῖν σῑ̆ροῖν toîn sī̆roîn |
τοῖς σῑ̆ροῖς toîs sī̆roîs | ||||||||||
Accusative | τὸν σῑ̆ρόν tòn sī̆rón |
τὼ σῑ̆ρώ tṑ sī̆rṓ |
τοὺς σῑ̆ρούς toùs sī̆roús | ||||||||||
Vocative | σῑ̆ρέ sī̆ré |
σῑ̆ρώ sī̆rṓ |
σῑ̆ροί sī̆roí | ||||||||||
Notes: |
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