Both are very different offerings – they are like chalk & cheese. Term insurance is a pure risk cover and a product which is an absolute must for every individual who has any dependent relying on their income. You typically should take a term insurance cover of 20 times your annual income. In term insurance, if you die, your nominee gets the sum assured. In case you survive the policy term, nothing is paid out to you. They are by far the cheapest form of cover.
Endowment Plans on the other hand are plans which are a combination of both insurance + investment. You get a life cover and you get an investment component also. You keep paying during the course of your policy term and at the end of the policy term you get a maturity amount. A variation of Endowment plans are Money Back plans where some part of the benefits are paid to you at regular intervals during the policy term itself. Usually the insurance cover you get in these plans is not great or sufficient for the policyholder’s dependents but they can be used as good investment tools. There is a sense of discipline and you keep paying regularly and build a corpus which can be used for some major cash requirement at the end of the policy term – say for your child’s higher education or marriage or for buying a house.