I have seen this term used in numerous ways. It can me what you described, adding chenille pieces, decorative stitching, the use of texture magic or texture thread, etc...
I guess it depends on which type the author is currently using/discussing LOL
Texture thread: you sew a design/pattern on fabric with it, give it a shot of steam and the thread shrinks leaving a "textured" look.
Texture magic: You apply it to the back of the fabric, sew a design/pattern with regular thread, give it a shot of steam and it shrinks leaving a "textured" look. :D:D:D