The same word had appeared in Revelation 12:9 to describe Satan’s expulsion from heaven. With the use of the verb “throw” the dragon is belittled, described as a thing to be tossed aside. In the present context he is a chained prisoner; his being thrown into prison (here the pit) indicates his helplessness.
3 and threw him into the pit, and shut it and sealed it over him, so that he might not deceive the nations any longer, until the thousand years were ended. After that he must be released for a little while.