Definitions
1.VerbTo enter suddenly or with force.
2.VerbTo enter or add to a conversation; to say (something) by way of interruption or addition to a conversation.
3.VerbTo take action; to become involved in a situation, so as to alter or prevent an action.
4.VerbTo ally oneself (with someone), to take (someone's) side.
5.VerbTo be or act in harmony (with something).