Please may someone tell me what this symbol means?
This is a character “立”。

The basic meaning of "立" is "standing straight". However, since the picture you put is a tattoo, it usually has a deeper meaning.

The "立" in a tattoo can be understood as "顶天立地" which means when a person stands, his head reaches the sky and his feet step on the ground. With a deeper meaning, a person can withstand all kinds of difficulties and disasters and do their best to solve them, and the people around him are therefore safe.