DEM：全称为Demurrage Charges。Demurrage 可以缩写为DM，意思是“滞期费”。

Demurrage：means a charge payable in the event the Buyer is unable to complete discharging the ship within agreed laytime.

集装箱在承运人或其代理人控制下的集装箱超期(逾期)使用费，通常指收货人清关提货前在目的地码头或堆场发生的集装箱超期使用费。船公司会一般会提供Free Demurrage，超过免费期后，就要收取Demurrage Charges。

DET：全称为Detention Charge。Detention 可缩写为DT，意思是“滞箱费”。

货物滞留在集装箱里，没有将空箱退出给船公司所产生的费用，这个费用一般由船公司收取。

一般来说，船公司给的Free Time（免费期限）= Free Demurrage+ Free Detention。

【拓展】Storage：堆存费，时间范围包括箱子从落到码头开始，一直到报关结束提出码头为止。不同于Demurrage，堆存费由港区收取，而非船公司。

参考双语例句：

The incumbent would handle the complex ship charters and cargo aircraft contracts on a daily basis and handle several disputed ship chartering contract cases, involving the resolution of disputes on liquidated damages and detention and demurrage charges in an aggregated amount of more than $1 million.

任职者将负责每天处理复杂的包船和货机合同，处理关于包船合同的若干争议，包括解决总额超过 100 万美元的违约赔偿以及扣留和滞期费争议。

If the shipment is on the freight collect basis but the consignee does not take delivery of the goods within 14 days from the date of the goods’ arrival at the place of delivery, the Customer shall be responsible for payment of all the outstanding freight charges, and costs and expenses (including but not limited to storage costs and demurrage charges) incurred until the goods are duly delivered or are sold or disposed of as per Clauses 8.2 and/or 8.3.

如货物运送以运费到付的方式进行，但收货人在货物到达交付地点之日起14天内并无接收货物，客户应负责支付所有未付运费，以及直至货物正式交付或根据第8.2条及/或8.3条出售或处置前产生的费用和开支(包括但不限于储存费和滞期费)。

The benefit of establishing this post would be evident in terms of customs clearances submitted within the accepted time frame, and therefore goods would be released on time, reducing the chances that demurrage would be charged for overdue containers.

设立这一员额的好处很明显，可保证在规定时间范围内提交结关材料，促使货物按时放行，从而减少因集装箱愈期停留而收取滞期费的现象。