This is the 9383rd most frequent Catalan word.
impregnen
"Impregnen" means "they impregnate" or "they soak."
Here, 'impregnen' is used metaphorically to indicate that the walls carry or are saturated with history.
Les parets de l'antiga casa impregnen història.
The walls of the old house are imbued with history.
In this case, 'impregnen' describes how the memories deeply influence or fill the individual's thoughts.
Els records de la infantesa impregnen els seus pensaments.
The memories of childhood permeate their thoughts.
Here, 'impregnen' is used to show how the scents spread and dominate the air in the garden.