This is the 4634th most frequent Turkish word.
birliklerini
"Their units" or "their troops."
Here, 'birliklerini' refers to 'their units' in the possessive and accusative case, showing the belonging to soldiers and the direct object of the verb 'koruyor' (protect).
Askerler birliklerini koruyor.
The soldiers protect their units.
Here, 'birliklerini' refers to 'their unity,' emphasizing a sense of togetherness or purpose, and is again in the possessive and accusative case.
Gönüllüler birliklerini güçlendirdi.
The volunteers strengthened their unity.
In this sentence, 'birliklerini' is used to denote 'his troops,' referring to entities under the command of the brigade commander, in the possessive and accusative case.