serv＝to serve（服务）,to keep（保持）
1 [U] ~ (of sth) keeping or observing (observe 2b) a law, custom, festival, holiday, etc （法律、习俗等的）遵守, 奉行; （节日等的）纪念
*the observance of school rules 对校规的遵守
* the observance of New Year's Day as a public holiday 把元旦当作公众节日的习俗.
2 [C] (fml 文) act performed as part of a religious or traditional ceremony 宗教仪式; 传统庆典
*religious observances 宗教仪式.
when someone obeys a law or does something because it is part of a religion, custom, or ceremony
the observance of a peace agreement
the strict observance of Islam
the Memorial Day observance
something you do as part of a ceremony, especially a religious ceremony
1. The company holds its people to strict observance of that code. 公司要求所属人员严格遵守那项规章制度。