Medical Definition of semicircular canal
: any of the loop-shaped tubular parts of the labyrinth of the ear that together constitute a sensory organ associated with the maintenance of bodily equilibrium, that consist of an inner membranous canal of the membranous labyrinth and a corresponding outer bony canal of the bony labyrinth, and that in all vertebrates above cyclostomes form a group of three in each ear usually in planes nearly at right angles to each other—see semicircular duct
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