The Collaborative International Dictionary of English v.0.48:

Od \Od\, n. [G., fr. Gr. ? passage.] (Physics)
   An alleged force or natural power, supposed, by Reichenbach
   and others, to produce the phenomena of mesmerism, and to be
   developed by various agencies, as by magnets, heat, light,
   chemical or vital action, etc.; -- called also odyle or the
   odylic force. [Archaic]
   [1913 Webster]

         That od force of German Reichenbach
         Which still, from female finger tips, burnt blue.
                                                  --Mrs.
                                                  Browning.
   [1913 Webster]

WordNet (r) 3.0 (2006):

o.d.
    v 1: dose too heavily; "The rock star overdosed and was found
         dead in his hotel room" [syn: overdose, o.d.]