Source : Webster's Revised Unabridged Dictionary (1913)

Piperazine \Pi*per"a*zine\, n. Also -zin \-zin\ . [Piperidine +
   azote + -ine.] (Chem.)
   A crystalline substance, {(C2H4NH)2}, formed by action of
   ammonia on ethylene bromide, by reduction of pyrazine, etc.
   It is a strong base, and is used as a remedy for gout.

Pyrazine \Pyr"a*zine\, n. Also -zin \-zin\ . [Pyridine + Gr. ?
   not + ? life.] (Org. Chem.)
   A feebly basic solid, {C4H4N2}, obtained by distilling
   piperazine with zinc dust, and in other ways. Also, by
   extension, any of various derivatives of the same.