This is the 7737th most frequent Catalan word.
centenària
A female who is one hundred years old or older.
Here, 'centenària' describes something (in this case, the farmhouse) that is a hundred years old or more.
La masia centenària és avui un museu.
The century-old farmhouse is today a museum.
In this example, 'centenària' is used to characterize the oak tree by age.
Vam plantar un roure centenària al jardí.
We planted a century-old oak in the garden.
'Centenària' here refers to the grandmother, signifying her long life of over a hundred years.