The Collaborative International Dictionary of English v.0.48:

Invariable \In*va"ri*a*ble\, a. [Pref. in- not + variable: cf.
   F. invariable.]
   Not given to variation or change; unalterable; unchangeable;
   always uniform.
   [1913 Webster]

         Physical laws which are invariable.      --I. Taylor.
   -- In*va"ri*a*ble*ness, n. -- In*va"ri*a*bly, adv.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

invariably \in*va"ri*a*bly\ adv.
   Always; in every case.
   [PJC]

WordNet (r) 3.0 (2006):

invariably
    adv 1: without variation or change, in every case; "constantly
           kind and gracious"; "he always arrives on time" [syn:
           constantly, invariably, always]