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]

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

Source: Webster's Revised Unabridged Dictionary (1913)