This is the 21st most frequent Finnish word.
siitä
"Siitä" means "about it," "from it," "of it," or "of that," depending on context.
In this sentence, 'siitä' is the elative form of 'se', used to indicate the thing being liked.
Pidän siitä.
I like it.
In this sentence, 'siitä' serves as the elative form of 'se', specifying the subject of thought or opinion.
Mitä mieltä olet siitä?
What do you think about it?
Here, 'siitä' refers to 'that', and indicates the event mentioned previously, functioning as a reference in the elative case.