Source : Webster's Revised Unabridged Dictionary (1913)

Trigesimo-secundo \Tri*ges"i*mo-se*cun"do\, n.
   A book composed of sheets so folded that each one makes
   thirty-two leaves; hence, indicating, more or less
   definitely, a size of book; -- usually written {32mo}, or
   32[deg], and called {thirty-twomo}.