From The Collaborative International Dictionary of English v.0.48 [gcide]:
Exhibitor \Ex*hib"it*or\, n. [Cf. L. exhibitor a giver.]
One who exhibits.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
exhibitor
n 1: someone who organizes an exhibit for others to see [syn:
exhibitor, exhibitioner, shower]