Proto-Baltic: *swid-u- adj., *swid-ē̂- (*swid-a-) vb., *swid- vb. inch., *swid-men-ā̂ f., *swid-mō̃ (-men-); *swī̂d- vb. inch. (2), *sweid- (*-ja-) vb tr.
Meaning: shine, light
Lithuanian: svidù- `blank, glänzend, flimmernd, flittern, glitzern', svidḗti, svìda `glänzen, flimmern, flittern, glitzern, blitzen', caus. svìdinti, ostlit. svìsti (sviñda, svìdō) 'zu glänzen beginnen, anbrechen (von Licht)', ostlit. svīsti (svīsta, svīdō) 'id.'; svidmenà, svidmuõ 'Glasur'
Lettish: svîst (svîstu, svîdu) `an-, hervorbrechen (vom Licht), tagen', sviestiês 'dass.'