Webster's Revised Unabridged Dictionary · 1913

Observance

Observance , noun

[French observance, Latin observantia. See Observant.]

1.
The act or practice of observing or noticing with attention; a heeding or keeping with care; performance; -- usually with a sense of strictness and fidelity; as, the observance of the Sabbath is general; the strict observance of duties.
It is a custom More honored in the breach than the observance. — Shakespeare
2.
An act, ceremony, or rite, as of worship or respect; especially, a customary act or service of attention; a form; a practice; a rite; a custom.
At dances These young folk kept their observances. — Chaucer
Use all the observance of civility. — Shakespeare
Some represent to themselves the whole of religion as consisting in a few easy observances. — Rogers
O I that wasted time to tend upon her, To compass her with sweet observances! — Tennyson
3.
Servile attention; sycophancy. [Obsolete]
Salads and flesh, such as their haste could get, Served with observance. — Chapman
This is not atheism, But court observance. — Beau. & Fl
Love rigid honesty, And strict observance of impartial laws. — Roscommon