What is the difference between annuity and pension?

Pension fund generates a one sum that can at some time be withdrawn and used. On the other hand annuities are a relatively secure income that starts paying out at one fixed date after you are finished working. Many people prefer annuity precisely because of this security aspect. Under Pensions you contribute periodically and create a lump sum upto a specified minimum Age. In UK it is currently 55. If you would like to stop accumulating at this age, you get a lump sum. With this lump sum you can start withdrawing in selected frequency (note that the capital(lump sum) gets depleted as you withdraw, unless the Capital is not generating any further income. On the other hand you can buy an Annuity, which is a periodic payment to you based on your lift expectancy (how long you live futher). This is called Secured Pension and the earlier withdrawal type is unsecured pension (because of depletion/the Funds under investment not doing good). In India, we call it as pension and annuity are clubbed together. That is you accumulate and start getting an income as Annuity under the same policy. Please note that when you decide to buy annuity with the accumulated amount, universally, you have an option called Commutation or Tax Free Cash (upto maximum of 25%) to take home in lump sum and the rest is used to give you annuity.