DuckCorp Dico

Found one definition

1.                 From WordNet (r) 3.0 (2006):
                   
   
   
                   
                     
   em
       n 1: a quad with a square body; "since `em quad' is hard to
            distinguish from `en quad', printers sometimes called it a
            `mutton quad'" [syn: em, em quad, mutton quad]
       2: a linear unit (1/6 inch) used in printing [syn: em, pica
    em, pica]