In economics what is the difference of debt vs deficit?

Deficit means imports more than exports. The deficit country needs hard currency, mostly USD, to pay for it. It might use the foreign resetves, or sell bonds in international markets to finance the deficit. In simple Keynesian model, the deficit occurs if the government has the budget deficit. That means expenditure exceeds the tax revenues. So the government hasto borrow the money to finance the budget deficit. So the deficit has become a public debt which hasto pay back by tax revenues. So public debts theoretically will come along with tax rise. In the  US, the Treasury will just issue bond to replace the old one which is expired. So it usually just pays for the interest.