Certificate of deposit accounts are short term investment options that are offered by banks. They pay higher interest than traditional savings accounts but have different rules and restrictions. CD's are not as liberal as MMF's. Usually the agreement is for at least 6 months and they are definitely not transaction friendly accounts. Typically you deposit the money and agree to leave it alone for the term that has been agreed upon, of course no one wants to keep your money, if you really need to get it out you can, but expect to pay penalties. If you remove the money before the end of the term you may wind up with less money than you put in.
Money Market Accounts
Money market accounts are also short term investment options that are offered by banks. They are more liberal than CD's and are similar to Money Market Funds. They are transaction friendly accounts, which mean that you can withdraw money without penalties.
Regular Savings Accounts
Regular or passbook savings accounts are a really safe place to park your money; they are virtually without risk, transaction friendly, but offer a much lower interest rate than most other short term investments. If you are more cautious than most this may be a nice safe option for you.
If you have some extra cash that you need to stash for a short period of time, why not look at short term investment options? You can earn money on your money while you are waiting to make a larger investment or purchase. There are many different options that are sure to fit most any situation.
Decide on your financial goals and than choose from one of the many short term investment options that are available.