infrasonic /in-frə-sonˈik/ (acoustics)

1. (of frequencies) below the usual audible limit
2. Of, using or produced by infrasonic vibrations or pressure waves

inˈfrasound noun

• eighth notes
• eight-hour
• eighths
• eighties
• eightieth
• eightieths
• eight-oar
• eight-oars
• eightpence
• eightpences
• eightpenny
• eights
• eightscore
• eightscores
• eightsman
• eightsmen
• eightsome
• eightsome reel
• eightsomes
• eight-square
• eightvo
• eightvos
• eighty
• eigne
• EIIR