This is the 14479th most frequent Spanish word.
étnicas
Ethnic.
Here, 'étnicas' describes the adjective attributing the noun 'comunidades' to ethnicity or ethnic-related characteristics.
Las comunidades étnicas respectivas poseen tradiciones únicas.
The respective ethnic communities have unique traditions.
In this sentence, 'étnicas' modifies 'costumbres,' indicating they originate or are associated with ethnic groups.
Celebramos las diversas costumbres étnicas.
We celebrate the diverse ethnic customs.
Here, 'étnicas' refers to issues related to ethnic groups or diversity, used in broad or abstract context.