An endowment fund is a foundation-created investment fund that makes regular withdrawals from its invested money. Universities, nonprofit organizations, churches, and hospitals frequently use the capital or money in endowment funds. Endowment funds are generally supported by tax-deductible contributions that are utilized for particular purposes.
Endowment Plan is an insurance product. In this plan apart from insurance a lumpsum amount at the maturity or in between is paid to investor. This is a not a market linked scheme, means money is not invested in stock market. But like ULIPs they are not very efficient schemes and returns (IRR) are usually less than 7% as money is used for insurance coverage also.
Premium is high due to high administrative charges for insured amount compared to Term Insurance, which is a pure insurance product. So, you wont get best of both the worlds and usually people prefer term insurance and separate investment product like mutual funds.