spelling and grammar checkers, computer programs that identify apparent misspellings and grammatical errors by reference to an incorporated dictionary and a list of rules for proper usage. They often appear as components of word-processing programs for personal computers or as stand-alone Web sites. Spelling checkers usually cannot identify spelling errors that result in another legitimate word (e.g., “form” typed for “from”) and are hard to use on documents that contain numerous words (e.g., foreign terms) not entered in the incorporated dictionary. Grammar checkers—which generally check punctuation, sentence length, and other aspects of style—have been criticized for their reliance on oversimplified rules.