含 - Now, CONTAIN It!

Readings & Meanings:

ガン

ふく（む）

ふく（める）

contain, include, keep in one's mouth

Common Usage:

含まれる

含み笑い

含有量

Examples:

この福神漬けには人工着色料が含まれている。

「今に分かりますよ。」と言って、彼は含み笑いをした。

この食品の塩分の含有量は10mgだ。

Translations:

These pickled vegetables are made with manmade food coloring products.

"Now I understand" he said with a barely-contained giggle.

This food's salt content amount is 10mg.

Radical:

口, kuchi, mouth, is the radical.

今 is the phonetic. Of course, we know it means "now," but the pictograph is of a cover over some kind of contents, meaning to conceal an object by covering it totally. (The idea of "now" came from the idea of seizing a moment--to catch prey, that is.)

Combined, they show something contained in the mouth, or otherwise contained.

References:

http://www.kanjinetworks.com/indices/radindex.html
http://www.thejapanesepage.com/node/kanji/7.htm