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señor (Noun) "lord;" (m.) "mister," (f.) "mistress"
11th cent. Old Spanish el señor "lord," la señor "lady." Feminine suffix -a (1) added to la señor due to hypercharacterization of its gender. From Latin senior "elder," but originally "older." From senex "old." From Proto-Italic *sen-ek- 'id.' From Proto-Indo-European *sen- 'id.'
Indo-European
Romance
Portuguese senhor, Catalan senyor, French seigneur, Italian signore, Sardinian sannori
Celtic
Gaulish Seno-gnatos "old birth," Old Irish sen "old," Middle Welsh hen 'id.,' Old Breton hen 'id.'
Germanic
Gothic sineigs "elderly," Balto-Slavic Lithuanian sẽnas "old," Latvian sęns 'id.'
Hellenic
Ancient Greek ἕνος (hénos) "old"
Armenian
Armenian hin "old"
Indo-Iranian
Sanskrit sána- "old," Avestan hana- 'id.'