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sangre m. (Noun) "blood"
12th cent. Old Spanish sangne, sangre. From Latin sanguinem, accusative of sanguis 'id.' From Proto-Italic *sanguen 'id.' From Proto-Indo-European *h1éh2-r- "blood." The suffix *-guen is of unknown meaning and unknown origin.
Indo-European
Romance
Asturian sangre, Portuguese sangue, Galician sangue, Catalan sangu, French sang, Italian sangue, Aromanian sãndzi, Romanian sânge, Sardinian sàmbani
Balto-Slavic
Latvian asins "blood"
Hellenic
Ancient Greek ἔαρ (héar) "blood"
Indo-Iranian
Sanskrit ásr̥j- "blood"
Tocharian
A ysār "blood," B yasar 'id.'

Old Spanish variant sangrue is anomalous. Perhaps under orthographic influence from Latin.