What's the difference between i.e. and e.g.?
late 14c., "something formed in the mind, thought, notion," from conceiven (see conceive) based on analogy of deceit and receipt. Sense evolved from "something formed in the mind," to "fanciful or witty notion" (1510s), to "vanity" (c.1600) through shortening of self-conceit (1580s).
figure of speech, usually a simile or metaphor, that forms an extremely ingenious or fanciful parallel between apparently dissimilar or incongruous objects or situations. The Petrarchan conceit, which was especially popular with Renaissance writers of sonnets, is a hyperbolic comparison made generally by a suffering lover of his beautiful and cruel mistress to some physical object-e.g., a tomb, the ocean, the sun. The metaphysical conceit, associated with the Metaphysical poets of the 17th century, is a more intricate and intellectual device. It usually sets up an analogy between one entity's spiritual qualities and an object in the physical world and sometimes controls the whole structure of the poem. For example, in the following stanzas from "A Valediction: Forbidding Mourning," John Donne compares two lovers' souls to a draftsman's compass:If they be two, they are two soAs stiffe twin compasses are two,Thy soule the fixt foot, makes no showTo move, but doth, if the'other doe.And though it in the center sit,Yet when the other far doth rome,It leanes, and hearkens after it,And growes erect, as that comes home