Noun

(en noun)

The act of demonstrating; showing or explaining something.

An event at which something will be demonstrated.

I have to give a demonstration to the class tomorrow, and I'm ill-prepared.

A public display of group opinion.

A show of military force.

A mathematical proof.

* , s.v. Thomas Hobbes:

He read the proposition. So he reads the demonstration of it, which referred him back to such a proposition,; which proposition he read.

Noun

(en noun)

The act of observing, and the fact of being observed.

*

, title=(The Celebrity), chapter=5 , passage=But Miss Thorn relieved the situation by laughing aloud,

* {{quote-magazine, year=2012, month=March-April, author=(Jeremy Bernstein)

, volume=100, issue=2, page=146, magazine=(American Scientist) , title= A Palette of Particles , passage=The physics of elementary particles in the 20th century was distinguished by the observation of particles whose existence had been predicted by theorists sometimes decades earlier.}}

The act of noting and recording some event; or the record of such noting.

A remark or comment.

* Shakespeare

That's a foolish observation .

* Alexander Pope

To observations which ourselves we make / We grow more partial for the observer's sake.

A judgement based on observing.

Performance of what is prescribed; adherence in practice; observance.

* Jeremy Taylor

We are to procure dispensation or leave to omit the observation of it in such circumstances.