確 - I'm CERTAIN That Bird Has a Stone

Readings & Meanings:

カク

たし（か）

たし（かめる）

make certain, certain

Common Usage:

確かめる

確認

確か

確定

Examples:

それが本当かどうか確かめる必要がある。

それが本当かどうか確認する必要がある。

これだけ勉強すれば、日本語検定２級合格は確かだ。

就職先が確定した。

Translations:

It's necessary to ascertain whether it's true or not.

It's necessary to confirm whether it's true or not.

If you only do this to study, passing the second-level of Japanese certification will be certain.

My next job has been decided.

Radical:

Ishi-hen, 石, will be our radical tonight.

The phonetic element is 隺. 隹 is a pictograph of a bird (a short and squat bird, not one with a long tail, like in 鳥). The cover 冖 adds the sense of that squat little bird flying over the horizon. A barely-visible speck in the sky.

石 is stone, of course. But think of it like a cold, hard fact. So you're investigating something hard to see and getting cold, hard facts, so as to be certain.

References:

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