an explicit comparison between two things using 'like' or 'as'. My love is as a fever, longing still For that which longer nurseth the disease, Shakespeare, Sonnet CXLVII Reason is to faith as the eye to the telescope. D. Hume [?] Let us go then, you and I, While the evening is spread out against the sky, Like a patient etherized upon a table... T.S. Eliot, The Love Song of J. Alfred Prufrock