The Collaborative International Dictionary
Isoclinal
Isoclinal \I`so*cli"nal\, Isoclinic \I`so*clin"ic\, a. [Iso- + Gr. ? to incline.] Of or pertaining to, or indicating, equality of inclination or dip; having equal inclination or dip.
Isoclinal lines (Magnetism), lines on the earth's surface connecting places at which a dipping needle indicates the same inclination or dip.
Wiktionary
isoclinal
a. Having equal inclination or dip. n. A line connecting places of equal inclination or dip.