This is the 11945th most frequent Turkish word.
girdiğin
"That you entered" or "which you entered."
In this sentence, 'girdiğin' indicates the action of entering ('yarışmaya') performed by the subject in the past.
Yarışmaya girdiğin için çok gururluyuz.
We are proud of you for entering the competition.
The word 'girdiğin' in this context specifies the exact moment someone entered a location ('eve').
Eve girdiğin an telefon çaldı.
The phone rang the moment you entered the house.
Here, 'girdiğin' is a qualifying expression describing the room ('oda') that someone has entered in the past.