The Collaborative International Dictionary of English v.0.48:

cortisol \cortisol\ n.
   a steroid hormone (C21H30O5) active in carbohydrate and
   protein metabolism; -- called also hydrocortisone. It is
   used in medicine as an antiinflammatory agent

   Syn: hydrocortisone.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

cortisol
    n 1: an adrenal-cortex hormone (trade names Hydrocortone or
         Cortef) that is active in carbohydrate and protein
         metabolism [syn: hydrocortisone, cortisol,
         Hydrocortone, Cortef]