infrasonic /in-frə-sonˈik/ (acoustics)

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

• perfumy
• perfunctorily
• perfunctoriness
• perfunctorinesses
• perfunctory
• perfusate
• perfusates
• perfuse
• perfused
• perfuses
• perfusing
• perfusion
• perfusionist
• perfusionists
• perfusions
• perfusive
• pergameneous
• pergamentaceous
• pergola
• pergolas
• pergunnah
• pergunnahs
• perh
• perhaps
• peri