Emily Dickinson Lexicon

A'GUE, n. [a'gu; Sax. æge, oga, or hoga, fear, horror; Arm. hegea, to shake; Goth. agis, fear, agyan or ogan, to fear; Ir. agh, fear, agha or aghaim, to fear. The radical idea is a shaking or shivering similar to that occasioned by terror.]

1. The cold fit which precedes a fever, or a paroxysm of fever in intermittents. It is accompanied with shivering.
2. Chilliness; a chill, or state of shaking with cold, though in health.
3. It is used for a periodical fever, an intermittent, whether quotidian, tertian, or quartan. In this case, the word, which signifies the preceding cold fit, is used for the disease.