定期存款，是指存款人将现金存入在银行机构开设的定期储蓄账户内，事先约定以固定期限为储蓄时间，以高于活期存款的利率获得回报，期满后可领取本金和利息的一种储蓄形式。如果存款人在未满约定储蓄期限的时候提取定期存款，银行通常会将利息予以折扣后发给储户或是按照活期存款的方式来处理这笔业务。在低利时代，大额定存可能会有较低的利率。储户在需要领取大额存款之前，往往会被要求提前一天通知银行申请预约提取，以备银行准备足够的现金予以支付。

A time deposit (also known as a certificate of deposit in the United States, a term deposit, particularly in Canada, Australia and New Zealand; a bond in the United Kingdom; Fixed Deposits in India, Malaysia and in some other countries) is a money deposit at a banking institution that cannot be withdrawn for a specific term or period of time (unless a penalty is paid). When the term is over it can be withdrawn or it can be held for another term. Generally speaking, the longer the term the better the yield on the money. In its strict sense, certificate deposit is different from that of time deposit in terms of its negotiability: CDs are negotiable and can be rediscounted when the holder needs some liquidity, while time deposits must be kept until maturity.