Etherproof E•ther•proof | adjective: impervious to; or designed to resist the penetration of, ether.

Revision period

A minor bird

I have wished a bird would fly away,
And not sing by my house all day;

Have clapped my hands at him from the door
When it seemed as if I could bear no more.

The fault must partly have been in me.
The bird was not to blame for his key.

And of course there must be something wrong
In wanting to silence any song.

-- Robert Frost

Revision period
noun
The time of year when the students that will pass examinations are troubled, and those that will fail are celebrating.