A spell checker is a software tool designed to identify and correct spelling errors in text. It works by comparing words in a document against a database of correctly spelled words. When it finds a misspelled word, it typically suggests alternatives, allowing users to choose the correct spelling. Spell checkers are commonly integrated into word processing programs like Microsoft Word and email clients. They can also be found in web browsers and mobile applications, helping users write more accurately. While useful, spell checkers may not catch every mistake, especially with homophones or context-specific words.