A Bilateral Loan is a kind of loan that involves a single borrower and a single lender. The lenders are usually banks or any other financial institution.
In contrast a Multilateral Loan is a kind of loan that involves a number of lenders and a single borrower. The lenders are most financial institutions or banks.
Multilateral loans is a common type of loan that is taken country wide. Normally the multilateral loans are funded by agencies such as International Monetary fund (IMF), World Bank, etc.