Source : Webster's Revised Unabridged Dictionary (1913)

Propagator \Prop"a*ga`tor\, n. [L.: cf. F. propagateur.]
   One who propagates; one who continues or multiplies.

Source : WordNet®

propagator
     n 1: someone who propagates plants (as under glass)
     2: someone who spreads the news [syn: {disseminator}]