what is the name and meaning of this symbol?

what is the name and meaning of this symbol? after the arrow in the attached image

[Stephen23]

https://en.wikipedia.org/wiki/Psi_(letter)

[Eliza]

thank you

Answer 1

[Jan]

This is the Greek uppercase psi. The meaning depends on the context. Of course you can call any function or variable "Psi". Actually you should find the definition in the surrounding text.

[Stephen23]

It looks like a lowercase italic psi to me.

[Star Strider]

@Stephen —

... and to me.