The Collaborative International Dictionary of English v.0.48:

Acromegaly \Ac`ro*meg"a*ly\ ([a^]k`r[-o]*m[e^]g"[.a]*l[y^]), n.
   [NL. acromegalia, fr. Gr. 'a`kron point, peak + me`gas,
   mega`loy, big.] (Med.)
   Chronic enlargement of many bones of the skeleton, especially
   bones of hands, feet and face; the condition is due to
   excessive secretion of growth hormone.
   [1913 Webster + AS]

WordNet (r) 3.0 (2006):

acromegaly
    n 1: enlargement of bones of hands and feet and face; often
         accompanied by headache and muscle pain and emotional
         disturbances; caused by overproduction of growth hormone by
         the anterior pituitary gland (due to a tumor) [syn:
         acromegaly, acromegalia]