This is the 997th most frequent Czech word.
všemi
The Czech word "všemi" means "by all" or "with all" in English.
Here, 'všemi' is the instrumental case of 'všechny', meaning 'all', used to match the case needed for the preposition 's' (with).
Všemi dětmi se přátelsky rozloučili.
They said goodbye warmly to all the children.
Here, 'všemi' again is in the instrumental case, used for showing the means or accompaniment, describing 'surrounded by'.
Na plese byl obklopen všemi tanečníky.
At the ball, he was surrounded by all the dancers.
In this sentence, 'všemi' matches the instrumental case required by the preposition 'se' (with).