bulk cargo是指大宗商品，没有包装，直接装在船上的。比如，粮食、石油和天然气等。
Commodity freight or bulk cargo refers to goods in large quantities which are not pre-packaged during shipment such as grain, oil, and other goods transported in loose mass. 
在集装箱出现之前，货物都是以break bulk cargo（散货）方式运输。 货物有包装，比如说以箱子、桶和托盘等方式包装运输。
简单来说，即不是bulk货物，也不是装在集装箱内，那么就是break bulk cargo了。
The second most popular type of cargo transportation method is break-bulk which originates from the word breaking bulk and it refers to goods that must be loaded individually. Normally these products cannot be in an intermodal shipping container and have to be transported in boxes, crates, barrels, or pallets instead.
Break-bulk cargo or general cargo is typically transported in ships called general cargo ships and it was the most common mode of transportation for the majority of shipping history until the introduction of containerization. Volume of break-bulk cargo has declined dramatically due to theft and damage during shipping; however, it is still employed to ship oversized freight which does not fit on a 40ft intermodal container. 
参考链接：
https://www.ademar.nl/en/break-bulk-vs-bulk-cargo/
https://www.varaallied.com.au/blog/break-bulk-shipping-vs-bulk-shipping-explained
http://www.gilbertusa.com/break-bulk-shipping-understanding-the-pros-and-cons/