As nouns the difference between observance and sabbatarian
is that observance
is the practice of complying with a law, custom, command or rule while sabbatarian
is a person who regards and keeps the seventh day of the week ("saturday", the israelite or jewish sabbath) as holy in conformity with the fourth commandment of the decalogue, such as an orthodox jew, seventh-day adventist, seventh day baptist, a member of the church of god (seventh day); a sabbath-keeper, a saturday-keeper.
As an adjective sabbatarian is
of or pertaining to the sabbath, or the tenets of sabbatarians.
* observaunce (obsolete)
The practice of complying with a law, custom, command or rule
The custom of celebrating a holiday or similar occasion
Observation or the act of watching
(religion) A rule governing a religious order, especially in the Roman Catholic church
* sabbatarian, sabbatharian,Sabbatharian
A person who regards and keeps the seventh day of the week ("Saturday", the Israelite or Jewish Sabbath) as holy in conformity with the fourth commandment of the Decalogue, such as an Orthodox Jew, Seventh-day Adventist, Seventh Day Baptist, a member of the Church of God (Seventh Day); a Sabbath-keeper, a Saturday-keeper.
A person who regards and keeps the first day of the week as holy and often considers it as a replacement for the seventh-day Sabbath, a Sunday-keeper.
A person who favors the strict observance of the Sabbath (either the seventh day or first day of the week).
A member of a non-Jewish religious sect originating in Russia distinguished by observance of Jewish rites and festivals including Saturday as the day of rest.
* sabbatarianism, Sabbatarianism
Of or pertaining to the Sabbath, or the tenets of Sabbatarians.