Wave
noun
The kanji and the word are exactly the same. That means they share meanings as well.
Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you to remember:
You jump on a wave and ride around the world on it. As you ride this wave, it gets bigger and bigger, until it reaches tsunami (なみ) proportions. Imagine looking down from the tsunami at the vast, blue sea all around you. That's quite a wave you're riding.
今日の波、すごく高いね。
Today's waves are very high, aren't they?
大へんだ！コウイチが波に飲みこまれたぞー！
OMG! Koichi has been swallowed by a wave!
波にゆらゆら揺られるのが気持ちいい。
The rocking of the waves to and fro feels good.