This is the 15th most frequent Czech word.
jsou
"Jsou" means "are" in English.
Jsou is used here as the verb 'to be' in the present tense, indicating a state of being for a plural subject (third-person plural).
Oni jsou šťastní.
They are happy.
Jsou appears as a connector between the subject (implied or explicitly mentioned) and its location, again as the verb 'to be' in the present tense.
Jsou tam na zahradě.
They are there in the garden.
Jsou functions as the verb 'to be' connecting the subject 'Věci' with their description or attribute, indicating a state of a plural noun.