圧 - Pressed Clay Makes a Good House

Readings & Meanings:

あつ

pressure

Common Usage:

気圧

圧政

Examples:

またまた、悩ましい低気圧がやってきます。。。
yahoo JP weather blog

圧制は革命の種子である。
JP trans. of a Daniel Webster quote.

Translations:

Yet again, a low pressure zone has turned up...

Repression is the seed of revolution. - Daniel Webster
(圧政 also means oppression, despotism, and power politics)

Bonus:

There's something familiar about 圧. Sure, we all know 土, but what's it doing in that half-box? That half-box is the radical.

Radicals will make your kanji-studying life a lot more pleasant. If you can learn to recognize them, suddenly you'll be familiar with a lot more kanji.

This radical, of the first top horizonatl stroke followed by a left-leaning downward stroke on the left, is called "Gan-dare" 厂. It looks like a roof and the left wing of a house, or a cliff if you like.

Others with this radical include 反 of 反対,　原 of 秋葉原, and 灰 of 灰皿.

References:

http://www.jlptstudy.com/2/index.html
Easy Kanji, by Fujihiko Kaneda (Amazon Link)
JapanesePod101.com
http://www.thejapanesepage.com/kanji/kanji/a.htm