IPA: /ˌɪnfrəˈsɒnɪk/
KK: /ɪnˈfrəʊsɒnɪk/
Relating to sound waves that have frequencies lower than what humans can hear.
The researchers studied infrasonic waves to understand their effects on the environment.
Infrasonic → It is formed from "infra-" (meaning below) and "sonic" (from Latin "sonus", meaning sound). The word "infrasonic" refers to sound waves that are below the range of human hearing.
Think of 'infra-' meaning below, and 'sonic' relating to sound — so infrasonic describes sounds that are below the hearing range.
No commonly confused words.