The Collaborative International Dictionary of English v.0.48:

Ect- \Ect-\, Ecto- \Ec"to-\ [Gr. 'ekto`s outside outside.]
   A combining form signifying without, outside, external.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ECT
    n 1: the administration of a strong electric current that passes
         through the brain to induce convulsions and coma [syn:
         electroconvulsive therapy, electroshock, electroshock
         therapy, ECT]