'directional' definitions:

Definition of 'directional'

From: WordNet
adjective
Relating to or indicating directions in space; "a directional microphone" [ant: omnidirectional]
adjective
Relating to direction toward a (nonspatial) goal; "he tried to explain the directional trends of modern science"
adjective
Showing the way by conducting or leading; imposing direction on; "felt his mother's directing arm around him"; "the directional role of science on industrial progress" [syn: directing, directional, directive, guiding]

Definition of 'directional'

From: GCIDE
  • directional \directional\ adj.
  • 1. of or pertaining to direction (definition 2). [WordNet 1.5]
  • 2. serving to indicate direction. [PJC]
  • 3. (Radio) transmitting radio signals in a specific direction, or receiving signals only from a narrow angle of directions, thus serving to indicate the direction from which radio signals are coming. Used of antennas; as, a directional antenna. [PJC]