The Collaborative International Dictionary of English v.0.48:

Starch \Starch\ (st[aum]rch), a. [AS. stearc stark, strong,
   rough. See Stark.]
   Stiff; precise; rigid. [R.] --Killingbeck.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Starch \Starch\, n. [From starch stiff, cf. G. st[aum]rke, fr.
   stark strong.]
   1. (Chem.) A widely diffused vegetable substance found
      especially in seeds, bulbs, and tubers, and extracted (as
      from potatoes, corn, rice, etc.) as a white, glistening,
      granular or powdery substance, without taste or smell, and
      giving a very peculiar creaking sound when rubbed between
      the fingers. It is used as a food, in the production of
      commercial grape sugar, for stiffening linen in laundries,
      in making paste, etc.
      [1913 Webster]

   Note: Starch is a carbohydrate, being the typical amylose,
         C6H10O5, and is detected by the fine blue color given
         to it by free iodine. It is not fermentable as such,
         but is changed by diastase into dextrin and maltose,
         and by heating with dilute acids into dextrose. Cf.
         Sugar, Inulin, and Lichenin.
         [1913 Webster]

   2. Fig.: A stiff, formal manner; formality. --Addison.
      [1913 Webster]

   Starch hyacinth (Bot.), the grape hyacinth; -- so called
      because the flowers have the smell of boiled starch. See
      under Grape.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Starch \Starch\, v. t. [imp. & p. p. Starched (st[aum]rcht);
   p. pr. & vb. n. Starching.]
   To stiffen with starch.
   [1913 Webster] Star chamber

WordNet (r) 3.0 (2006):

starch
    n 1: a complex carbohydrate found chiefly in seeds, fruits,
         tubers, roots and stem pith of plants, notably in corn,
         potatoes, wheat, and rice; an important foodstuff and used
         otherwise especially in adhesives and as fillers and
         stiffeners for paper and textiles [syn: starch, amylum]
    2: a commercial preparation of starch that is used to stiffen
       textile fabrics in laundering
    v 1: stiffen with starch; "starch clothes"

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "starch":
   aggressiveness, albumen, bang, batter, bonnyclabber, butter,
   carbohydrate, clabber, cornstarch, cream, curd, dash, dough, drive,
   egg white, enterprise, fire, gaum, gel, gelatin, get-up-and-go,
   getup, ginger, glair, glop, glue, gluten, go, goo, gook, goop,
   gruel, gumbo, gunk, hydroxy aldehyde, hydroxy ketone, initiative,
   jam, jell, jelly, kick, loblolly, molasses, monosaccharide,
   mucilage, mucus, pap, paste, pep, pepper, piss and vinegar,
   pizzazz, polysaccharide, polysaccharose, poop, porridge, pudding,
   pulp, punch, puree, push, putty, rob, saccharide, semifluid,
   semiliquid, size, snap, soup, spunk, sticky mess, sugar, syrup,
   thrust, treacle, trisaccharide, verve, vim, vitality, zing, zip