This is the 908th most frequent Portuguese word.
comerciais
"Comerciais" means "commercials" or "related to commerce/business" in English.
In this sentence, 'comerciais' refers to commercial breaks on television or radio, serving as an adjective modifying 'intervalos' (breaks).
Os intervalos comerciais interrompem o programa frequentemente.
The commercial breaks frequently interrupt the program.
Here, 'comerciais' describes areas dedicated to commerce or trade, functioning as an adjective modifying 'áreas' (areas).
As áreas comerciais da cidade são muito movimentadas.
The commercial areas of the city are very busy.
In this usage, 'comerciais' again acts as an adjective, characterizing 'jingles' (advertising tunes) as being related to commerce or promotion.