isoclinal Syllabification: (i·so·cli·nal)Pronunciation: /ˌīsəˈklīnl/Definition of isoclinal adjective Geology denoting a fold of strata so acute that the two limbs are parallel. Origin: mid 19th century (denoting 'equal magnetic inclination'): from iso- 'equal' + Greek klinein 'to lean, slope' + -alisoclinal in other Oxford dictionaries Definition of isoclinal in the British & World English dictionary