Main Entry: gy·ro·com·pass

Pronunciation: \ˈjī-rō-ˌkəm-pəs also -ˌkäm-\

Function: noun

Date: 1910

: a compass consisting of a continuously driven gyroscope whose spinning axis is confined to a horizontal plane so that the earth's rotation causes it to assume a position parallel to the earth's axis and thus point to the true north