Do Definitions Change over Time?

In diachronic (or historical) linguistics, semantic change is a change in one of the meanings of a word. Every word has a variety of senses and connotations, which can be added, removed, or altered over time, often to the extent that cognates across space and time have very different meanings.

Why do definitions change?

The alteration of meaning occurs because words are constantly used and what is intended by speakers is not exactly the same each time. If a different intention for a word is shared by the speech community and becomes established in usage then a semantic change has occurred.

Do definitions change?

What's worth keeping in mind is that meanings don't change over night. Different meanings of the same word often overlap, and new meanings can co-exist with older meanings for centuries.