In 1871 Lewis Henry Morgan introduced a two-part kinship terminology typology that distinguished between descriptive and classificatory terminologies. His typology has been problematic even since Morgan proposed it. In 1909 A. Kroeber denied that Morgan's typology was valid since there are descriptive kin terms and classificatory kin terms in every kinship terminology. However, Kroeber's argument misunderstands the conceptual difference between descriptive and classificatory kinship terminologies. More recently, David Schneider has also rejected Morgan's typology but on the basis that it depends on using western concepts relating to kinship terminologies and he concluded that there is no such thing as a kinship terminology since Morgan's typology assumed all kinship terminologies are based biologically on procreation. Schneider's argument is also faulty since he did not realize that basing kinship terminologies on procreation can be rejected without rejecting the concept of a kinship terminology. In this paper, I show that Morgan's typology is conceptually grounded on the distinction between primary sibling terms and compound sibling terms. Terminologies with primary sibling terms give rise to classificatory terminologies and terminologies with compound sibling terms give rise to descriptive kinship terminologies.