This is the 442nd most frequent Greek word.
καθημερινά
"Καθημερινά" means "daily" or "every day."
The word 'καθημερινά' is used here as an adverb meaning 'daily'.
Διαβάζω εφημερίδες καθημερινά.
I read newspapers daily.
In this context, 'καθημερινές' is an adjective related to 'καθημερινά', describing 'συνήθειες' (habits).
Οι καθημερινές συνήθειες είναι σημαντικές.
Daily habits are important.
Here, 'καθημερινά' also acts adverbially to describe the frequency of the action denoted by the verb 'περιλαμβάνει'.