Words are the basic building blocks of grammar. Words are combinations of letters and sounds, individual words are separated by spaces. Some words contain more than one part, such as hyphenated words and other compound words. Some words are pronounced in the same way but carry different meanings. As time passes, the definition of a word or is pronunciation may change radically from its inception to its current usage.
Words may be combined into phrases. Some phrases become popular over the years and are applied to situations other than originally intended. These phrases take on a figurative meaning rather than a literal meaning, and become idioms. If a certain phrase or idiom becomes popular only in a certain region or among a certain group of people, it becomes a colloquialism. And finally, a phrase that is misheard and misquoted may become a mondegreen or an eggcorn, sometimes supplanting the original phrase in popularity.