This is the 2185th most frequent Turkish word.
milli
"Milli" means "national" in English.
In this sentence, the word 'Milli' refers to the concept of 'national', describing something that pertains to a nation or country.
Milli bayramlarımız milletimizin birlik ve beraberlik sembolleridir.
Our national holidays are symbols of our nation's unity and solidarity.
Here, 'Milli' is used as an adjective to describe 'takım' (team) as associated with the nation, indicating a representation at the national level.
Milli takıma yeni oyuncular katıldı.
New players have joined the national team.
In this case, 'Milli' denotes something that is a shared heritage or treasure of the entire nation.