This is the 207th most frequent Czech word.
tyto
"Tyto" means "these" in English.
The word 'tyto' here is used as a demonstrative adjective to specify that it's these particular books being referred to.
Tyto knihy jsou velmi zajímavé.
These books are very interesting.
In this context, 'tyto' points to specific documents the speaker and listener are aware of.
Zapomněl jsi si přinést tyto dokumenty?
Did you forget to bring these documents?
Here, 'tyto' indicates particular things the speaker is referring to on the table.