Sight words, often also called high frequency sight words, are commonly used words that young children are encouraged to memorize as a whole by sight, so that they can automatically recognize these words in print without having to use any strategies to decode

Sight words are critical to reading not only because they are used so frequently, but also because many of them cannot easily be sounded out or illustrated. ... Because they are used so often it is important that readers be able to recognize these words on sight (hence the term “sight words”).

Sight words are words that should be memorized to help a child read and write. Learning sight words means that your child will be able to recognize them at a glance, and won’t need to break the words down letter-by-letter, thus making reading easier and faster.