This is the 2751st most frequent Spanish word.
leído
"Leído" means "read" (past participle of "leer").
Here 'leído' is the past participle of the verb 'leer' used in the present perfect tense to indicate an action completed recently or relevant to the present.
He leído muchos libros este año.
I have read many books this year.
In this case, 'leído' describes the state or condition of the book, indicating that it has been read many times or extensively.
El libro que me prestaste está muy leído.
The book you lent me is very read.
The word 'leído' is again used as the past participle in a perfect tense, specifying her extensive reading activities in the past.