12. A derivative word is one made up of a root and one or more formative elements: as, manly, goodness, runner.
The formative elements are called prefixes and suffixes. (See §§ 16, 17.)
13. By Composition.—With respect to their composition, words are divided into two classes,—simple and compound words.
14. A simple word consists of a single significant term: as, school, master, rain, bow.
15. A compound word is one made up of two or more simple words united: as, school-master, rainbow.
In some compound words the constituent parts are joined by the hyphen as school-master; in others the parts coalesce and the compound forms a single (though not a simple) word, as rainbow.
III.—PREFIXES AND SUFFIXES.
16. A prefix is a significant syllable or word placed before and joined with a word to modify its meaning: as, unsafe = not safe; remove = move back; circumnavigate = sail around.
17. A suffix is a significant syllable or syllables placed after and joined with a word to modify its meaning: as, safely = in a safe manner; movable = that may be moved; navigation = act of sailing.