The Collaborative International Dictionary of English v.0.48:

Steady \Stead"y\, v. t. [imp. & p. p. Steadied (-[i^]d); p.
   pr. & vb. n. Steadying.]
   To make steady; to hold or keep from shaking, reeling, or
   falling; to make or keep firm; to support; to make constant,
   regular, or resolute.
   [1913 Webster]

WordNet (r) 3.0 (2006):

steadying
    adj 1: causing to become steady; "had a steadying effect on her
           nerves"