Shin Eun-Kyong. 2002. A Diachronic Study on the Meaning of the "tteom(틈)". Korean Semantics, 11. In this work, I reviewed the meaning of the 'theom' for the research of diachronic change of lexical meaning of Korean word and studied the mechanism of semantic extension from base meaning. The base meaning of the 'theom' is 'an aperture' and this has been extended to the temporal concepts as 'time to spare', 'an opportunity' and 'an estrangement'. This conclusion is correspond with the claim that the filed of grammaticalization have the course of change from concrete objects to abstract meaning. I observed many examples of lexical items with the 'theom' and found that some words appear in modern age and some items like the 'theom-seori' have the different meaning from middle age in modern use. I hope this data would contribute to explanation of the process of semantic change in gap concept expressions.