The Collaborative International Dictionary of English v.0.48:

Mercerize \Mer"cer*ize\, v. t. [imp. & p. p. -ized; p. pr. &
   vb. n. -izing.] [From (John) Mercer (1791-1866), an English
   calico printer who introduced the process + -ize.]
   To treat (cotton fiber or fabrics) with a solution of caustic
   alkali. Such treatment causes the fiber to shrink in length
   and become stronger and more receptive of dyes. If the yarn
   or cloth is kept under tension during the process, it assumes
   a silky luster. -- Mer`cer*i*za"tion, n.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

mercerize
    v 1: treat to strengthen and improve the luster; "mercerize
         cotton" [syn: mercerize, mercerise]