Plural of cornetcy; the rank, position, or commission held by a cornet (a junior cavalry officer), or the period of holding such a position.
From 'cornet' (a cavalry rank) plus '-cy' suffix forming nouns from adjectives or titles, creating the abstract noun for the office. Emerges in 17th-century military terminology.
In British cavalry, a cornetcy was actually one of the first officer ranks—young wealthy men would buy a cornetcy as their entry ticket to military leadership!
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