This is the 912th most frequent Czech word.
tato
The Czech word "tato" means "this" (feminine form).
In this context, 'tato' is a demonstrative pronoun meaning 'this', referring to 'kniha' (book).
Tato kniha je velmi zajímavá.
This book is very interesting.
Here, 'tato' is used as a demonstrative pronoun meaning 'this', referring to 'dívka' (girl).
Kdo je tato dívka na fotce?
Who is this girl in the photo?
In this usage, 'tato' is used for plural, meaning 'these', referring to 'pravidla' (rules).