f. and mod. birta, u, f. [Goth. bairhti], brightness, light, the old form birti is used Luke ii. 9, in the N. T. of 1540, and the Bible of 1584, and still kept in the 11th Ed. of Vidal. (1829); otherwise birta, Pass. 8. 19, 41. 10; birta also occurs Stj. 81, Fb. i. 122; but otherwise birti in old writers; birti ok fegrð, Fms. v. 344, x. 347; birti ægis, the gold, Edda 69; tunglsins birti, Stj. 26, Fms. i. 77.