Dictionary.net

One of the portions of space bounded by the three coordinate planes. Specif. (Crystallog.), one of the parts of a crystal into which it is divided by the axial planes.

One of the portions of space bounded by the three coordinate planes. Specif. (Crystallog.), one of the parts of a crystal into which it is divided by the axial planes.

sek'tant, n. a portion of space cut off from the rest by three planes, but extending to infinity.