This is the 10250th most frequent French word.
industrielles
"Industrielles" means "industrial" (feminine plural).
Here, 'industrielles' is an adjective and describes the characteristic of the cities as being related to industry.
Les villes industrielles ont joué un rôle clé dans le développement économique.
Industrial cities played a key role in economic development.
In this sentence, 'industrielles' serves as an adjective and refers to machines associated with industry or manufacturing.
Les machines industrielles nécessitent un entretien régulier.
Industrial machines require regular maintenance.
Here, 'industrielles' acts as an attribute, qualifying 'techniques' as pertaining to the industrial sector.