The Collaborative International Dictionary of English v.0.48:

Ratihabition \Rat`i*ha*bi"tion\ (-h[.a]*b[i^]sh"[u^]n), n. [L.
   ratihabitio; ratus fixed, valid + habere to hold.]
   Confirmation or approbation, as of an act or contract. [Obs.]
   --Jer. Taylor.
   [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

RATIHABITION, contracts. Confirmation; approbation of a contract;
ratification. Vin. Ab. h.t.; Assent. (q.v.)