A dictionary attack is a type of cyber attack that involves systematically trying a large number of words or phrases in an attempt to guess a password or encryption key. This method relies on the use of a pre-existing list of commonly used words, phrases, or combinations, known as a dictionary, to quickly and efficiently test for possible matches. This attack is often used by hackers to gain unauthorized access to a system or account, and can be particularly effective against weak or easily guessable passwords. It is important for individuals and organizations to use strong, unique passwords to protect against dictionary attacks and other forms of cyber threats.