1.VerbMust; need to; to be urged to; to be required to; indicates obligation.
"You have to wear a seat belt.; I have to go to the bathroom.; I just have to have that shirt.; Wise men speak because they have something to say; fools because they have to say something.; She said you had not to talk to me, but you don't have to obey her anymore."
2.VerbMust; expresses a logical conclusion.
"that has to be the postman; it has to be an electrical fault"