A morpheme is the smallest unit of language that carries meaning. It can be a word or a part of a word that cannot be divided into smaller meaningful segments without changing its meaning or leaving a meaningless remainder. There are two types of morphemes: free morphemes, which can stand alone with a specific meaning (e.g., "eat," "date"), and bound morphemes, which cannot stand alone with meaning and are typically affixes that occur before or after a base (e.g., "un-" in "undo," "-ed" in "walked"). Morphemes are important for understanding reading, spelling, vocabulary, and comprehension, as they provide a key to independently work out the meaning and pronunciation of words