Wiktionary
texton
n. A basic microcomponent of an image that may be recognised visually before the entire image is.
Wikipedia
Texton
The term texton was introduced by Bela Julesz in 1981 to describe "the putative units of pre-attentive human texture perception." The term reemerged in the late 1990s and early 2000s to describe vector quantized responses of a linear filter bank.