This is the 13708th most frequent German word.
eintreten
"To enter" or "to occur."
In this sentence, 'eintreten' is used figuratively to mean advocating or standing up for something.
Ich werde für Ihre Rechte eintreten.
I will advocate for your rights.
Here, 'eintreten' is used literally to signify physically entering through a space or location.
Die Tür öffnete sich und jemand trat ein.
The door opened and someone entered.
Again, 'eintreten' is used in a figurative sense, addressing standing up for a cause or an ideal.