adj.
Pronunciation: ˌ s ə b- ' sä-nik
Function: adjective
Etymology: International Scientific Vocabulary
Date: 1937
1 : of, relating to, or being a speed less than that of sound in air
2 : moving, capable of moving, or utilizing air currents moving at a subsonic speed
3 : INFRASONIC 1
– sub · son · i · cal · ly \ -ni-k( ə -)l ē \ adverb