Dictionary of Root Words: Greek and Latin Roots

What are “Root Words”?
A root, or root word is a word which is used to form another word. It is also called a base word. A root does not have a prefix (A letter or group of letters added to the beginning of a word) or a suffix (A letter or group of letters added to the end of a word).
Root is the primary lexical unit of a word, and of a word family

For example, pure is a root. By adding prefixes and suffixes, the following words could be made:
impure, purity, pureness

Similarly, play and move are root words. By adding prefixes and suffixes, the following words could be made:
plays, played, playing, player
moving, movement, moved, movable, mover, movingly

In this book, the author has given most common Greek and Latin roots which are used in English language.