When two words are used together to yield a new meaning, a compound is formed.
Compound words can be written in three ways: as open compounds (spelled as two words, e.g., ice cream), closed compounds (joined to form a single word, e.g., doorknob), or hyphenated compounds (two words joined by a hyphen, e.g., long-term).
Sometimes, more than two words can form a compound (e.g., mother-in-law).
