This is the 16261st most frequent Turkish word.
yanını
"Yanını" means "your side" or "your vicinity" in English.
In this sentence, 'yanını' refers to 'his/her side' as a location or accompaniment.
Onun yanını terk ettim.
I left his/her side.
Here, 'yanını' implies an object or place near the person being addressed.
Kitabı yanını almayı unutma.
Don't forget to take the book by your side.
In this case, 'yanını' metaphorically suggests 'one's side' as an area of concern or defense.