The Collaborative International Dictionary of English v.0.48:

analgesic \an`al*ge"sic\ ([a^]n`[a^]l*j[=e]"z[i^]k or
   [a^]n'l*j[=e]"z[i^]k), a. [NL., fr. Gr. 'analghsi`a; 'an
   priv. + 'a`lghsis sense of pain.] (Med.)
   Serving to reduce the sensibility to pain without loss of
   consciousness. AS
   [PJC]

The Collaborative International Dictionary of English v.0.48:

analgesic \an`al*ge"sic\ ([a^]n`[a^]l*j[=e]"z[i^]k), n. [NL.,
   fr. Gr. 'analghsi`a; 'an priv. + 'a`lghsis sense of pain.]
   (Med.)
   a medication which serves to reduce the sensibility to pain
   without loss of consciousness. Aspirin and acetaminophen
   (paracetamol, trade name Tylenol) are commonly used
   non-prescription analgesics. --AS
   [PJC + AS]

WordNet (r) 3.0 (2006):

analgesic
    adj 1: capable of relieving pain; "the anodyne properties of
           certain drugs"; "an analgesic effect" [syn: analgesic,
           analgetic, anodyne]
    n 1: a medicine used to relieve pain [syn: analgesic,
         anodyne, painkiller, pain pill]