1. [n]  the feel of a surface or a fabric; "the wall had a smooth texture"
2. [n]  (fine arts) the characteristic appearance of a surface having a tactile quality
3. [n]  the musical pattern created by parts being played or sung together; "then another melodic line is added to the texture"
4. [n]  the essential quality of something; "the texture of Neapolitan life"

1. \Tex"ture\, n. [L. textura, fr. texere, textum, to
   weave: cf. F. texture. See {Text}.]
   1. The act or art of weaving. [R.] --Sir T. Browne.
   2. That which woven; a woven fabric; a web. --Milton.
            Others, apart far in the grassy dale, Or roughening
            waste, their humble texture weave.    --Thomson.
   3. The disposition or connection of threads, filaments, or
      other slender bodies, interwoven; as, the texture of cloth
      or of a spider's web.
   4. The disposition of the several parts of any body in
      connection with each other, or the manner in which the
      constituent parts are united; structure; as, the texture
      of earthy substances or minerals; the texture of a plant
      or a bone; the texture of paper; a loose or compact
      texture.
   5. (Biol.) A tissue. See {Tissue}.
   

2. \Tex"ture\, v. t. [imp. & p. p. {Textured}; p. pr. & vb.
   n. {Texturing}.]
   To form a texture of or with; to interweave. [R.]
   

A measure of the variation of the intensity of a surface, quantifying properties such as smoothness, coarseness and regularity. It's often used as a region descriptor in image analysis and computer vision.

The three principal approaches used to describe texture are statistical, structural and spectral. Statistical techniques characterise texture by the statistical properties of the grey levels of the points comprising a surface. Typically, these properties are computed from the grey level histogram or grey level cooccurrence matrix of the surface.

Structural techniques characterise texture as being composed of simple primitives called "texels" (texture elements), that are regularly arranged on a surface according to some rules. These rules are formally defined by grammars of various types.

Spectral techiques are based on properties of the Fourier spectrum and describe global periodicity of the grey levels of a surface by identifying high energy peaks in the spectrum.