Which term describes a process where a word's meaning narrows?

The term that describes a process where a word's meaning narrows is "narrowing." This linguistic phenomenon occurs when a word that once had a broader meaning becomes more specific over time. For example, the word "meat" originally referred to any kind of food but has now come to specifically mean the flesh of animals. This illustrates how the meaning of a word can evolve and become more confined to particular contexts, which is the essence of narrowing.

The other terms refer to different processes in language change. Broadening, for example, is the opposite of narrowing, where a word's meaning expands to include more concepts. Commonisation refers to a proper noun becoming a common noun. Semantic shift is a general term that encompasses various types of change in word meanings, including both broadening and narrowing, but does not specifically define the process of a word's meaning becoming narrower.