Hit the Nail on the Head

A carpentry image with a long, well-documented history in English. An early version appears around 1438 in The Book of Margery Kempe, and the phrase in something close to its modern figurative sense, meaning exactly right rather than literally accurate hammer work, shows up in John Heywood's proverb collection in 1546. Hitting a nail squarely, rather than at an angle that bends it or misses entirely, takes real precision, making it a natural metaphor for getting something exactly correct. The ancient Romans had a near -identical expression, "rem acu tetigisti" ("you have touched the thing with a needle").