rimbase
/ˈrɪmbeɪs/Now historical
noun
Each of the two bodies of metal (originally cylindrical) forming a junction between the trunnions and the main shaft of a cannon, field gun, etc.
Origin
Early 19th century. From rim + base, apparently showing folk-etymological alteration of French embase, specifically use of embase supporting or reinforcing part from embase- (in embasement continuous pedestal under a building from en- + base + -ment, after Italian imbasamento).