From Proto-Italic *smeiros, from Proto-Indo-European *sméyros (“laughing, smiling”), from *smey- (“to laugh, to be glad”). Cognate with Sanskrit स्मेर (sméra), Swedish smila (“to smile”), Middle High German smielen (“to smile”), Old High German smierōn (“to smile”), Old English smerian (“to laugh at”), Old English smercian, smearcian (“to smile”), English smile.