To Begin
Something Begins, To Start, Something Starts
intransitive verb, godan verb
This word consists of kanji with hiragana attached. Because the hiragana ends with an う sound, you know this word is a verb.
This is an intransitive verb. That means it does not take a direct object. Something starts. No direct object here. That's why this verb means to start.
Since this word has okurigana (hiragana attached to the kanji) you know that it's probably going to be the kun'yomi reading.
Lucky for you, the kanji readings for transitive and intransitive verbs are almost always the same. Once you learn one, you know them both! This reading is the same as 始める.
夏休みはいつから始まりますか？
When will summer vacation start?
走って！コンサートが始まっちゃうよ！
Run! The concert is starting!
三時になると、おやつの時間が始まる。
Snack time begins at three o'clock.