This is the 454th most frequent Icelandic word.
loka
To close or shut.
Here, 'loka' means to physically close something, in this case, the doors.
Ég ætla að loka dyrunum.
I am going to close the door.
In this sentence, 'loka' is used to indicate the time when the store ceases its operations.
Verslunin lokar klukkan sex.
The store closes at six o'clock.
Here 'loka', or a variation 'ljúka', is employed metaphorically to signify finishing or concluding an activity or task.