Source : Webster's Revised Unabridged Dictionary (1913)

Henry \Hen"ry\, n.; pl. {Henrys}. [From Joseph Henry, an
   American physicist.]
   The unit of electric induction; the induction in a circuit
   when the electro-motive force induced in this circuit is one
   volt, while the inducing current varies at the rate of one
   amp[`e]re a second.