If you are in doubt about your choice, ask your CA Domain Committee member to offer an opinion before you submit the application. A two-character organizational string will only be acceptable when it clear that the string already forms part of the organization's corporate identity, e.g. when two characters represent its organizational identity in its logo. All single-character names are reserved for future use. Geographical place names, such as municipality and province names, are reserved at the federal, provincial, and territorial registration levels. Obscene names are not permitted.
Legal characters are letters, digits, and the hyphen.
You may mix upper and lower case, or use all upper or all lower case. Software will ignore case, and users can type in whatever case they like. You should capitalize your subdomain name as you wish it to appear in machine generated lists, such as the return address generated in your outgoing electronic mail. Hyphens may be used to separate words if necessary or consistent with normal references to the proper name of your organization. It is your responsibility to ensure that you have the right to use the name you have chosen.