ordnance

The word 'ordnance' originated as a clipped and altered form of Middle English 'ordinance,' which meant an arrangement, decree, or military provision. This, in turn, came from Old French 'ordenance,' derived from Latin 'ordinantia,' meaning 'arrangement' or 'order,' from the verb 'ordinare' (to arrange, set in order). The specific military sense of weapons and equipment developed in the late 15th century, referring to the orderly arrangement and provision of military materials. Over time, the pronunciation and spelling of 'ordinance' shifted to 'ordnance' exclusively for this military meaning, while 'ordinance' retained its general sense of an authoritative rule or decree, demonstrating how a specialized branch of meaning can linguistically diverge from its source.

The word is a simplex form. It is a variant spelling and pronunciation of the word "ordinance," which has undergone a specialized semantic shift in a military context.