The OED provides six different senses, with examples from the 13th century onward. This is the list of senses, and I have given the most recent examples of each.
I. Interrogative uses.
For the dependent or indirect interrogative use, and its distinction from the relative, cf. what pron., adj.1, and adv. I.
- For what? esp. for what purpose or end? (Often scarcely distinguishable from 2.)
a1616 Shakespeare Comedy of Errors (1623) iii. i. 40 E. Ant... Open the dore. S. Dro. Right sir, Ile tell you when, and you'll tell me wherefore. Ant. Wherefore? for my dinner.
1667 Milton Paradise Lost iv. 657 But wherfore all night long shine these..?
1846 A. Marsh Father Darcy xxix, Here I am—wherefore come, I have to learn.
- For what cause or reason? on what account? why? (Freq. with ellipsis; often coupled with why for emphasis.)
1853 Dickens Bleak House xx. 193 If he be ever asked how, why, when, or wherefore, he shuts up one eye and shakes his head.
1873 H. W. Longfellow Michael Angelo i. iv, But wherefore should I jest?
II. Relative uses.
- For which. Now distinguished by stress and spelling (whereˈfor).
1600 Shakespeare Henry V v. ii. 1 Peace to this meeting, wherefore we are met.
1913 Act 3 & 4 Geo. V c. 20 §118 (1) (d) All sums (not exceeding..one hundred pounds) due in respect of compensation under the Workmen's Compensation Act, 1906, the liability wherefor accrued before the said date.
- On account of or because of which; in consequence or as a result of which. Chiefly with n. (esp. reason or cause) as antecedent. arch.
1597 R. Hooker Of Lawes Eccl. Politie v. lxiii. 151 The true reason wherfore Christ doth loue belieuers is because their belief is the gift of God.
1829 R. Southey Sir T. More II. 187 The reason is sufficiently manifest wherefore a preference for republican institutions should hitherto have been shown.
- a. Introducing a clause expressing a consequence or inference from what has just been stated: On which account; for which reason; which being the case; and therefore. (Now always ˈwherefore.)
1842 Tennyson Morte d'Arthur in Poems (new ed.) II. 15 More things are wrought by prayer Than this world dreams of. Wherefore, let thy voice Rise like a fountain for me night and day.
1882 W. Besant All Sorts of Men II. xxix. 238 A person, you see, is an individual, or an indivisible thing. Wherefore, let us not despise our neighbour.
5b - obsolete
- as n. A question beginning with wherefore, or (more usually) the answer to such question; cause, reason. Often following why similarly used.
1838 Dickens Oliver Twist II. xxx. 184 They will have the why and the wherefore, and take nothing for granted.
1884 A. S. Swan Dorothea Kirke xiv, I am carried back to the days when I rebelled and demanded the wherefore of all God's dealings with me.