Definition of "headach"

This does not seem much like joy, indeed, in me—(twinkling away a tear or two)—but it will be very trying for us to part with her, after having had her so long, and she has a dreadful headach just now, writing all the morning:—such long letters, you know, to be written to Colonel Campbell, and Mrs. Dixon.

1815 December (indicated as 1816), [Jane Austen], chapter VIII, in Emma: […], volume III, London: […] [Charles Roworth and James Moyes] for John Murray, page 137

A headach induced Lady Alicia to leave before the opera was half over.

1831, L[etitia] E[lizabeth] L[andon], chapter 9, in Romance and Reality. […], volume I, London: Henry Colburn and Richard Bentley, […], page 78

She presented the symptoms of bilious pleura-pneumonia: violent headach and little delirium, vomiting, tongue blood-red at the edges; yellow tint of the face, pleuritic stitch; sputa moulded; great oppression; respiration almost extinct at the base of the chest, &c.

1833, R. J. Bertin, translated by Charles W. Chauncy, Treatise on the Diseases of the Heart, and Great Vessels, Philadelphia: Carey, Lea & Blnachard, page 24