This is the 2297th most frequent Turkish word.
bıçak
Knife.
The word 'bıçak' is used as a noun representing a physical object, a knife.
Keskin bir bıçak, mutfakta çok işe yarar.
A sharp knife is very useful in the kitchen.
The word 'bıçağı' is the accusative form of 'bıçak', indicating it is the direct object of the verb 'hold'.
Bıçağı dikkatlice tut, aksi halde kesebilirsin.
Hold the knife carefully, or else you might cut yourself.
The word 'bıçağımı' is in the possessive form, showing ownership, and 'eski' describes it as old.