This is the 16th most frequent French word.
sont
"Are" (third person plural of "être").
In this sentence, 'sont' is the third person plural form of the verb 'être' (to be), indicating the state of being of 'Ils' (They)
Ils sont heureux.
They are happy.
In this context, 'sont' is used in a demonstrative sentence, emphasizing the identification of 'mes amis' (my friends) as a description of 'Ce' (These).
Ce sont mes amis.
These are my friends.
Here, 'sont' serves as a link between the subject 'Les fleurs' (The flowers) and the adjective 'belles' (beautiful), expressing a characteristic.