harbour 一般用词，指停泊船只、装卸货物的天然或人工港口。
port 多指人工港口，还可指有港口的市。
wharf 指船只停泊装卸货物的码头。
pier 专指与海岸成直角形而突出的码头，可供旅客，货物上下船或供人散步用。
seaport 指港埠。
参考例句
1. We put off from the pier yesterday morning. 我们的船昨天早上从码头开出。
2. During the storm, the boat broke loose from the pier. 在暴风雨中这只船突然松开而离开了码头。
3. The widened section, usually concrete, at the base or bottom of a foundation wall, pier or column. 被加宽的部分，通常是混凝土，在基础墙壁，柱桩或支撑柱体的基础或底部。
英英解释
n.
1. a platform built out from the shore into the water and supported by piles; provides access to ships
2. (architecture) a vertical supporting structure (as a portion of wall between two doors or windows)
3. a support for two adjacent bridge spans
