This is the 326th most frequent Estonian word.
kõiki
"Kõiki" means "all" or "everyone" in English (partitive case).
Here, 'kõiki' (translated as 'everyone') is used to refer inclusively to all individuals who contributed, emphasizing gratitude towards them collectively.
Tänan kõiki, kes mulle abiks olid.
I thank everyone who helped me.
In this instance, 'kõiki' denotes the totality of the 'rules', stressing that there are no exceptions and every single rule is included in the statement.
Kõiki reegleid tuleb järgida.
All rules must be followed.
The word 'kõiki' (translated as 'all') is in the partitive case here, used to indicate that the action of inviting applies to 'all' in general, covering every individual in the group referred to as 'my friends'.