This is the 12581st most frequent Portuguese word.
territoriais
"Territoriais" means "territorial" in English, relating to territory.
Here, 'territoriais' qualifies 'fronteiras' to indicate that the borders being referred to are related to territories.
As fronteiras territoriais foram redefinidas após o acordo.
The territorial borders were redefined after the agreement.
In this case, 'territoriais' modifies 'questões' to signify that the issues discussed are concerned with territories or land disputes.
Os governos debateram sobre as questões territoriais durante a conferência.
The governments debated territorial issues during the conference.
The word 'territoriais' describes 'mudanças', emphasizing that the changes pertain to territory or land demarcation.