a fowl. a bird.
four heads. These are not interpreted, and will be understood only when they are seen. It will have these four heads at the time of its being seen.
Related Commentaries of Daniel 7:6
Daniel 7:6
6 After this I beheld, and lo another, like a leopard, which had upon the back of it four wings of a fowl; the beast had also four heads; and dominion was given to it.