An instrument for measuring the intensity of photogenic rays and computing the power of object glasses.

(medicine, cardiology) Specialized heart muscle cells that transmit electrical impulses from the AV node in the heart to the muscle cells of the heart wall, which contract in response producing the...

A person who works, often on a voluntary basis, in a relief agency.

A treelike data structure each of whose nodes has up to eight children, most often used to partition a three-dimensional space by recursively subdividing it.