This is the 42nd most frequent French word.
leurs
"Their" (possessive adjective).
Here, 'leurs' is a possessive adjective modifying the noun 'amis,' indicating possession related to a plural subject ('their' as it refers to multiple people or owners).
Leurs amis sont venus dîner hier.
Their friends came to dine yesterday.
In this sentence, 'leurs' functions as a possessive adjective, describing 'affaires' to show the items are owned by the subject 'they' (plural ownership).
Ils ont rangé leurs affaires avant de partir.
They put away their belongings before leaving.
Here, 'leurs' is a possessive adjective modifying 'voitures,' pointing to possession where numerous people own the cars in question.