di·rec·tion·al 
(dĭ-rĕkshə-nəl, dī-)
(dĭ-rĕkshə-nəl, dī-)adj.
1. Of or indicating direction: an automobile's directional lights.
2. Electronics Capable of receiving or sending signals in one direction only.
3. Relating to guidance in effort, behavior, or thought: directional training.
n.
A directional signal.
di·rec′tion·ali·ty (-shə-nălĭ-tē) n.