[equa.to.ri.al] adj (1664) 1 a: of, relating to, or located at the equator or an equator; also: being in the plane of the equator "a satellite in ~ orbit" b: of, originating in, or suggesting the region around the geographic equator
2. a: being or having a support that includes two axles at right angles to each other with one parallel to the earth's axis of rotation "an ~ telescope" b: extending in a direction essentially in the plane of a cyclic structure (as of cyclohexane) "~ hydrogens"--compare axial