A grammar checker is software or a program feature found in a word processor and is used to find grammatical errors. That is to say, it checks for improper sentence structure and word usage (e.g., their instead of there), poorly placed or unnecessary punctuation, and other more esoteric errors. An example of a software program that includes its own grammar checker is Microsoft Word. Microsoft Word underlines grammar errors with a green squiggly underline as shown in the picture.

Proofreading, Software terms, Spell check, Word processor terms

Press the F7 to start the spelling and grammar checker in Microsoft Word and most word processors.

  • See our top 10 online services and applications for a list of all top online services, including Grammarly.
  • Try the free grammar checker Grammarly, a great online service that checks for all types of grammar errors, and can even detect plagiarism.