What is "praetextas"

Praetexta \Pr[ae]*tex"ta\, n.; pl. Pr[ae]text[ae], E. Pr[ae]textas. [L. (sc. toga), fr. praetextus, p. p. of praetexere to weave before, to fringe, border; prae before + texere to weave.] (Rom. Antiq.) A white robe with a purple border, worn by a Roman boy before he was entitled to wear the toga virilis, or until about the completion of his fourteenth year, and by girls until their marriage. It was also worn by magistrates and priests.