An "IRA" is an "Individual Retirement Account".  IRA accounts provide tax advantages when people invest in these funds, because someone saving in an IRA doesn't have to pay taxes until the money is withdrawn. This makes the IRA an ideal account for those saving for retirement. IRAs are sometimes referred to as an "Individual Retirement Arrangement".

In a Roth IRA, you make contributions with money you've already paid taxes on (after-tax) and your money may potentially grow tax-free, with tax-free withdrawals in retirement, provided that certain conditions are met^.  Withdrawal of retirement funds from "Roth IRAs" have no tax penalty, because the money you invest are made after you pay taxes on the money.

Tax benefits	Federal tax-free growth, tax-free withdrawals1
Account fees2	None
Eligibility (age)3	None
Eligibility (income)	Must have employment compensation
IRA maximum contribution	$5,000 annually ($6,000 if 50 or older)
Minimum to open	Depends on wich company you use, some even $500 to set up
Withdrawals	No minimum required distribution during the lifetime of the original owner