首次 (shǒu cì) means “first; first time; for the first time”. It is an HSK 6 Chinese word in the HSK 3.0 vocabulary.
Practice each character:
宇航员首次登上了月球。
Yǔhángyuán shǒucì dēng shàng le yuèqiú.
Astronauts landed on the moon for the first time.
Updated: 2026-07-18