WordNet (r) 3.0 (2006):

sideward
    adv 1: toward one side; "turn the figure sideward" [syn:
           sideward, sidewards]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "sideward":
   ascending, axial, back, back-flowing, backward, crabwise,
   descending, down-trending, downward, drifting, flanking, flowing,
   fluent, flying, glancing, going, gyrational, gyratory, lateral,
   laterally, lee, leeward, mounting, next-beside, passing, plunging,
   progressive, reflowing, refluent, regressive, retrogressive,
   rising, rotary, rotational, rotatory, running, rushing, side,
   sideling, sidelong, sidewards, sideway, sideways, sidewise,
   sinking, skirting, soaring, streaming, up-trending, upward,
   weather, windward