Another kind of typo--informally called an "atomic typo"--is a typo that happens to result in a correctly spelled word that is different from the intended one. Since it is spelled correctly, a simple spellchecker cannot find the mistake. The term was used at least as early as 1995 by Robert Terry.

A few illustrative examples include:
* "now" instead of "not",
* "unclear" instead of "nuclear"
* "you" instead of "your"
* "Sudan" instead of "Sedan"