In brief
Sound consists of vibrations in the air. The outer ear collects them and directs them through the ear canal to the eardrum.
What it can mean in daily life
The eardrum and tiny middle-ear bones pass the vibrations to the cochlea. Hair cells there turn movement into nerve signals that the brain interprets as sound.
Next steps
Hearing also involves interpretation. The brain uses context and experience to understand speech when a word is unclear.