What are the acceptable lengths (number of characters) for TLD labels?
Ordinarily, TLD labels (e.g., “com”) that are proposed for the new TLD program should be between three and sixty-three characters long, inclusive. Two-letter codes must be available for establishing ccTLDs according to the policy set forth in ICP-1. Under that policy, ccTLDs are established with two-letter codes that appear on the ISO 3166-1 list. To avoid the possibility of future name collision, proposals for two-letter TLDs will not be accepted in the new TLD program unless the ISO 3166 Maintenance Agency has indicated that the proposed two-letter code will not be placed on the ISO 3166-1 list in a way that would be incompatible with the proposal. Compatibility could be demonstrated, for example, for a proposed TLD not meeting the alpha-2 code format used in the ISO 3166-1 list (e.g., “a1”) or where the Maintenance Agency has reserved the proposed code, in a manner compatible for the proposed usage under the new TLD program, for stated “particular applications” including Internet TL
