Definition of the word sink in

The phrase "sink in" originated in the mid-19th century, and it's meaning is to comprehend or understand something fully and deeply. The word "sink" originally meant "settle or fall into a position", as in objects sinking into water or into the ground. Over time, the usage of the word "sink" extended to mean understanding or learning something in a deeper and more profound way. The phrase "sink in" started to be used as a figurative expression in the late 1800s to describe the process of absorbing or fully grasping a concept or idea. In essence, the idea is supposed to "settle" or "fall" into a person's mind, similar to an object sinking into water. The phrase is often used in situations where a person initially struggles to understand a concept, but gradually comes to a complete understanding of it. Today, "sink in" is commonly used in everyday conversation to convey the process of gaining insight or comprehension.