IEEE Std 802.1AS-2020 uses both “domain number” and “domainNumber”. The former is the concept, while the latter is the attribute, parameter, or name of the respective field. There are 38 instances of the former, and 66 instances of the latter. In contrast, IEEE Std 1588-2019 uses “domainNumber” almost exclusively; there is one instance of “domain numbers” and 106 instances of “domainNumber”. It appears that at least some of the instances of “domain number” in 802.1AS-2020 should be “domainNumber. It would be useful to go through the document, check the usage of “domain number” and “domainNumber”, and change one to the other where necessary.