队长 (duìzhǎng) is a noun meaning "captain," "team leader," or "squad leader." It combines 队 (team/group) and 长 (chief/leader). It is used for leaders of sports teams, military squads, and other organized groups, and also appears in titles like 惊奇队长 (Captain Marvel).
他是我们篮球队的队长,打球特别厉害。
Tā shì wǒmen lánqiú duì de duìzhǎng, dǎ qiú tèbié lìhai.
He is the captain of our basketball team and is an amazing player.
队长决定今天下午加练一个小时。
Duìzhǎng juédìng jīntiān xiàwǔ jiā liàn yí gè xiǎoshí.
The captain decided to add an extra hour of practice this afternoon.
大家一致选她当新队长。
Dàjiā yízhì xuǎn tā dāng xīn duìzhǎng.
Everyone unanimously chose her as the new captain.