jot or tittle

The very smallest detail(s) or amount(s). "Jot," derived from the word for the Greek letter "iota," is a small amount, while a "tittle" is the dot over a lowercase i. Typically used in negative constructions to mean nothing at all. Not a single jot or tittle goes past the eye of the boss without her noticing. Make sure no jot or tittle in this contract is out of place. We can't afford to lose money over some typo or technicality.

The slightest change. In the King James version of Matthew 5:18 we read, “For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.” A “jot” was an iota, a very small quantity (we still use the expression “not one iota of truth”); a tittle was a tiny accent mark. Accordingly, to have said “not one jot or tittle” was a very erudite way of refusing to make even the most minor alteration.