This is the 12516th most frequent Spanish word.
metieron
"Metieron" means "they put in" or "they inserted."
The verb 'metieron' is used in the sense of 'inserted' or 'placed' something into a confined space.
Ellos metieron la caja en el armario.
They put the box in the closet.
Here, 'metieron' refers to 'scoring' a goal, metaphorically placing the ball into the goal.
Los jugadores metieron un gol al final del partido.
The players scored a goal at the end of the match.
In this context, 'metieron' is part of the reflexive expression 'se metieron en problemas', meaning 'to get into trouble'.