1. [n]  a midwestern state in central United States
2. [n]  a polyvalent metallic element that resembles chromium and tungsten in its properties; used to strengthen and harden steel

Mo
This biography of the Congressman and one time Presidential candidate focuses on his life in Arizona and his dedication to public service, which clearly took its toll on his personal life. The author examines key issues with which Udall was identified, many of which are still being argued: the environment, campaign reform, etc.

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1. \Mo\, a., adv., & n. [Written also {moe}.] [AS. m[=a]. See
   {More}.]
   More; -- usually, more in number. [Obs.]
         An hundred thousand mo.                  --Chaucer.
         Likely to find mo to commend than to imitate it.
                                                  --Fuller.
   

2. \-mo\
   A suffix added to the names of certain numerals or to the
   numerals themselves, to indicate the number of leaves made by
   folding a sheet of paper; as, sixteenmo or 16mo; eighteenmo
   or 18mo. It is taken from the Latin forms similarly used; as,
   duodecimo, sextodecimo, etc. A small circle, placed after the
   number and near its top, is often used for -mo; as, 16[deg],
   18[deg], etc.
   

The country code for Macau.