1Spring; the season after winter when flowers bloom and the weather warms.
春になると桜が一斉に咲く。
When spring comes, the cherry blossoms bloom all at once.
春の陽気で散歩に出かけた。
I went for a walk in the pleasant spring weather.
新しい学年は春に始まる学校が多い。
Many schools start the new academic year in spring.
2A classical/literary sense meaning the New Year — reflecting how, under the old lunar calendar, the new year began around the start of spring. Essentially unused as a standalone word in modern Japanese; it survives only as a faint echo in set greeting phrases.
3The prime or heyday of life or an endeavor, metaphorically likened to 'spring' — especially common in the set phrase わが世の春 ('one's own golden age').
彼はわが世の春を謳歌している。
He is enjoying the peak of his glory.
会社が急成長し、まさにわが社の春が来た。
The company grew rapidly, and it was truly our company's golden age.
4A literary sense referring to adolescence/puberty — the period of physical and mental maturation, metaphorically likened to 'spring.'
少女はやがて春を迎え、大人の女性へと変わっていった。
The girl eventually came of age and grew into an adult woman.
彼はまだ春を迎えたばかりの少年だった。
He was still just a boy who had barely reached adolescence.
5A literary, euphemistic sense referring to sexual desire or romance — mostly surviving in set phrases like 春をひさぐ ('to sell one's body'); rarely used as a standalone word.
困窮の末、彼女は春をひさぐことになった。
In the end, out of desperation, she was forced to sell her body.