What is the meaning of "and co."?
You can take as example the company name: Miller and co. The company consists not only of Mr. Miller, but it is an association. The co. means the group of people associated with that person. If a company is called e.g. Nottingham Co., it could register a domain name nottingham.co. The domain name nottingham.co is mirroring 1:1 the company name. Also Miller and co. could get a domain name http://millerand.co or miller-and.co, but in this case, the domain name is not so elegant.