This chapter aims to define the grammatical function and the relevant meaning of numeral classifiers in Korean. We focus on the descriptive function of numeral classifiers in relation to their head nouns, especially advocating the semantic relevance between numeral classifiers and their possible head nouns. In support of claiming the descriptive function of classifiers, the formation of compound nouns from classifiers and their possible head nouns will be examined. Those classifiers constructing compound nouns retain their descriptive meaning but lose their function as numeral classifiers. We claim numeral classifiers keep the descriptive function in numeral classifier phrases, leaving the task of counting or measuring to the numerals that accompany the classifiers. A corpus analysis has shown that numeral classifiers are decreasing in current Korean and that the general numeral classifier kay ‘CL’ is normally prevalent in use. Also, numerals not accompanying classifiers are often preferred in current Korean. Classifiers may help describe the fundamental nature of their head nouns.