What is define shallow?

Shallow can refer to different things depending on the context, but generally it means something with a small depth or height, or something that lacks depth or substance.

In terms of water, shallow refers to an area of a body of water that is not very deep, usually reaching only to a few feet or meters. This can make it safer for swimming in some cases but also may limit the kinds of boats or watercraft that can navigate in that area.

In geology, a shallow earthquake or tremor refers to one that occurs near the earth's surface, typically no deeper than several tens of kilometers or less. This can affect how much damage is caused by the earthquake and how it is measured or monitored.

In a more figurative sense, shallow can describe a person or an idea that lacks depth or substance. For example, a shallow person may be more concerned with superficial appearances or material possessions rather than deeper values or relationships. A shallow idea might be simplistic or lacking in nuance or complexity.