If something is snatched from you, it is stolen, usually using force. If a person is snatched, they are taken away by force.
强抢 • If your bag is snatched, let it go.
A snatch of a conversation or a song is a very small piece of it.
(谈话或歌曲的) 片断 • I heard snatches of the conversation. 我听到几段零星的谈话。