Grammar. 1  Also called objective case. (in English and some other languages) a case specialized for the use of a form as the object of a transitive verb or of a preposition, as him in The boy hit him, or me in He comes to me with his troubles. 2  a word in that case.
pinning-a mutual promise of a couple not to date anyone else; on college campuses it was once signaled by the giving of a fraternity pin. promise-a verbal commitment by one person to another agreeing to do (or not to do) something in the future.
3. any of various forms of fasteners, badges, or ornaments consisting essentially or partly of a penetrating wire or shaft (often used in combination): a fraternity pin; a tiepin. 4. a. a short metal rod, as a linchpin, driven through holes in adjacent parts, as a hub and an axle, to keep the parts together.