The Collaborative International Dictionary of English v.0.48:

Usual \U"su*al\, a. [L. usualis, from usus use: cf. F. usuel.
   See Use, n.]
   Such as is in common use; such as occurs in ordinary
   practice, or in the ordinary course of events; customary;
   ordinary; habitual; common.
   [1913 Webster]

         Consultation with oracles was a thing very usual and
         frequent in their times.                 --Hooker.
   [1913 Webster]

         We can make friends of these usual enemies. --Baxter.
   [1913 Webster] -- U"su*al*ly, adv. -- U"su*al*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

usual
    adj 1: occurring or encountered or experienced or observed
           frequently or in accordance with regular practice or
           procedure; "grew the usual vegetables"; "the usual summer
           heat"; "came at the usual time"; "the child's usual
           bedtime" [ant: unusual]
    2: commonly encountered; "a common (or familiar) complaint";
       "the usual greeting" [syn: common, usual]

Moby Thesaurus II by Grady Ward, 1.0:

133 Moby Thesaurus words for "usual":
   accepted, accustomed, arranged, average, banal, besetting,
   bourgeois, businesslike, central, characteristic, chronic, common,
   commonplace, conformable, consuetudinary, conventional, current,
   customary, distinctive, distinguishing, dominant, epidemic,
   established, everyday, exemplary, expected, familiar, formal,
   frequent, frequentative, garden, garden variety, garden-variety,
   generally accepted, habitual, hackneyed, harmonious, household,
   in hand, intermediary, intermediate, many, many times, mean,
   medial, median, mediocre, medium, methodical, middle-class,
   middle-of-the-road, middling, moderate, natural, naturalistic,
   no great shakes, normal, normative, not rare, obtaining,
   of common occurrence, oft-repeated, oftentime, old, ordered,
   orderly, ordinary, pandemic, plastic, popular, predictable,
   predominant, predominating, prescribed, prescriptive, prevailing,
   prevalent, prosaic, quintessential, rampant, realistic, received,
   recurrent, regnant, regular, regulation, reigning, rife, routine,
   ruling, run-of-mine, run-of-the-mill, running, same, sample, set,
   standard, steady, stereotyped, stock, suburban, symmetrical,
   systematic, the common, the commonplace, the normal, the ordinary,
   the usual, thick-coming, time-honored, traditional, trite,
   true to form, true to type, typal, typic, typical, unexceptional,
   uniform, unimaginative, universal, unnoteworthy, unoriginal,
   unremarkable, unspectacular, vernacular, well-known, well-ordered,
   well-regulated, widespread, wonted, workaday, worn out