貝 - SHELL out

Readings & Meanings:

かい

seashell, shellfish

Common Usage:

貝殻

貝塚

貝

Examples:

海岸で貝殻を拾う。

要するに貝塚は大昔の人々のゴミ捨て場の遺跡である。

貝の食中毒で死にそうになった。

Translations:

I gather seashells on the shore.

The point is, this heap of seashells is the remains of an ancient people's trash site.

I almost died of seafood poisoning.

Radical:

貝 is its own radical, Kai-hen. It's from a pictograph of a clamlike shellfish. The original pictograph split the box in half vertically, to more resemble a bivalve.

As we've seen in all the kanji we've already looked at with Kai-hen, this radical almost always imparts the meaning of "goods, wealth, money, commodities," because shells used to be used as currency.

References:

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