The Collaborative International Dictionary of English v.0.48:
ninepenny \ninepenny\ adj. 1. 2-3/4 in or 7 cm long; -- used of nail size; as, a ninepenny nail. [WordNet 1.5] 2. costing 9 cents (US) or 5 pence (Britain). [WordNet 1.5]WordNet (r) 3.0 (2006):
ninepenny adj 1: used of nail size; 2 3/4 in or 7 cm long