Correct in every detail; verbatim. The term comes from the nineteenth-century stage, in which actors were told to memorize their parts precisely to the letter of every word. It probably evolved from an earlier expression, to the letter, which had very much the same meaning. “I will obey you to the letter,” wrote Byron (Sardanapalus, 1821).

Exactly right, especially in appearance. This term, from the twentieth century, alludes to the precise resemblance of a painting or photograph to its subject, as in “The day was picture perfect for a picnic—not a cloud in the sky.” Time magazine used the term as the caption for a photograph of the presidential candidate Al Gore, his wife Tipper, running mate Joe Lieberman, and Lieberman’s wife Hadassah, calling it “the purest moment of their campaign” (Aug. 21, 2000).

The more one does something, the better at it one becomes. This ancient proverb began as use makes perfect. In English it dates from the fifteenth century but probably was a version of a much older Latin proverb. It exists in many languages, so presumably most people agree. Ralph Waldo Emerson almost did: “Practice is nine-tenths,” he wrote (Conduct of Life: Power, 1860). An English writer in the Spectator of May 10, 1902, differed: “Practice never makes perfect. It improves up to a point.”