A vocabulary answer key is the companion to a vocabulary test. The vocabulary answer key is identical to the vocabulary test, but it also shows the correct answers.
Vocabulary answer keys are commonly used by instructors to provide an easy way to grade tests. After having students take a vocabulary test, the teacher compares each student's test to the master vocabulary answer key to determine if students have answered each question correctly. The answer key allows the teacher to quickly and easily identify and mark student work without having to memorize the answers. Answer keys are often provided at the end of a text book.