The Collaborative International Dictionary of English v.0.48:

Mastigophora \Mas"ti*go*phor`a\, prop. n. [NL., fr. Gr. ma`stix,
   ma`stigos, a whip + fe`rein to bear.] (Zool.)
   A phylum of protozoans the kingdom Protista, consisting
   mainly of free-living flagellated unicellular organisms,
   lacking photosynthetic capability. Some members are
   pathogenic in man.
   [PJC]

WordNet (r) 3.0 (2006):

Mastigophora
    n 1: protozoa having flagella [syn: Mastigophora, class
         Mastigophora, Flagellata, class Flagellata]