This is the 57th most frequent Estonian word.
kogu
The Estonian word "kogu" means "whole," "entire," or "collection."
In this sentence, 'kogu' is used as an adjective meaning 'entire, whole', describing the noun 'raamatu' (book).
Ma lugesin kogu raamatu läbi.
I read the entire book.
Here, 'kogu' again acts as an adjective meaning 'whole', modifying the noun 'kogemus' (experience).
Kogu kogemus oli imeline.
The entire experience was wonderful.
In this sentence, 'kogu' is used as a noun meaning 'collection', specifying a group or set of objects.