Plain English Meaning
A part of the inner ear that senses tilting and straight-line motion. Tiny stone-like crystals sit on hair cells, and when your head tips or speeds up, the crystals slide and tell your brain what your body is doing.
Full Definition
A sensory structure in the inner ear that detects linear acceleration and the position of the head relative to gravity. The otolith organs (the utricle and saccule) contain hair cells topped with tiny calcium carbonate crystals; when the head tilts or accelerates in a straight line, these crystals shift and bend the hair cells, signaling the brain about motion and orientation.
Context Anchor
Seen in instrument flying discussions about the inner ear and why body sensations can disagree with the flight instruments.
Derivation
From Greek 'oto-' meaning ear and 'lithos' meaning stone. The name describes the small crystals (literally 'ear stones') that sit on the and make the organ .