Tawrat is the name of the revealed scripture associated with Moses. Classical lexical explanations differ concerning the derivation of the word, sometimes discussing senses related to light becoming visible or concealed information being disclosed.
Such etymological proposals need not be treated as certain historical origins. The scripture's standing follows from its divine revelation, not from a disputed root.
A possible etymology and a theological proof have different evidential force; disagreement over a name's derivation does not invalidate belief in the revealed book.