i was using it as a general term for whatever money you receive after you retire except personal investments or savings. i could not find out how 401ks work, specifically i did not find out whether 401k works like any other pension scheme or not. the wikipedia page on pensions does not say that 401k is not a pension, therefore i figure it is included in the definition.

i just checked the 401k page, and it says: a 401(k) plan is an employer-sponsored, defined-contribution, personal pension (savings) account.

so it's a pension.

but what we call it doesn't really matter. more important is the question if the payout depends on future generations paying in. in my brief search i could not tell whether the 401k is protected against that or if it even can be protected. but if it is i'll have to retract my claim. my apologies.