1. (用于公司名称中)
Co. is used as an abbreviation for (缩略 =) company when it is part of the name of an organization.

e.g. ...the Blue Star Amusement Co.
蓝星娱乐公司

2. (用于郡名之前，尤指爱尔兰的郡)
Co. is used as a written abbreviation for(书面缩略 =)county before the names of some counties, especially in Ireland.

e.g. ...Co. Waterford.
沃特福德郡

3. (用于人名之后)及其一伙，以及其他成员
You use and co. after someone's name to mean the group of people associated with that person.

e.g. Wayne Hussey and co. will be playing two live sets each evening.
韦恩·赫西和他的乐队每天晚上都将进行两场现场表演。