"Textual variants" refers to differences or alterations found in different versions or copies of a written text, such as a book or document. These variations can be in spelling, word choice, punctuation, or even entire sentences. Full definition
The most probable conclusion to draw from passages of this sort is that either Thomas or earlier Gnostic tradition made use of the canonical gospels at points where we find parallels, and that there is no reason to suppose that any passage in Thomas (in spite of interesting textual variants) provides an earlier or a more reliable version of any saying of Jesus. (religion-online.org)