Congratulation
Congratulations, Celebration, Festival, Congratulatory Gift
noun, verbal noun
This is the noun version of the kanji celebrate, so when you put a お before it to raise it up, it means congratulations! When someone has something to celebrate you should congratulate them.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You learned this reading already so you should be able to read it!
引っ越しのお祝いを渡さなくちゃいけないわね。
We have to bring a moving gift.