Of or pertaining to. Adjectival suffix appended to various words, often nouns, to produce an adjective form. Often added to words of Latin origin, but used with other words also. · Forming nouns, especially of verbal action.
Borrowed from Late Latin spīnālis (“of or belonging to the spine”), from spīna (“a prickle, spine”) + -ālis (“-al”, adjectival suffix). By surface analysis, spine + -al.