星期四 + Time/Event
星期四 (xīngqīsì) means "Thursday," the fourth day of the week in the Chinese system. Days of the week in Chinese are formed by 星期 (week) followed by a number from one to six, with Sunday being 星期天 or 星期日. Thursday uses the number 四 (four) because it is the fourth weekday.
我们星期四下午有一个会议。
Wǒmen xīngqīsì xiàwǔ yǒu yí gè huìyì.
We have a meeting on Thursday afternoon.
你星期四有空吗?我们一起吃晚饭吧。
Nǐ xīngqīsì yǒu kòng ma? Wǒmen yìqǐ chī wǎnfàn ba.
Are you free on Thursday? Let's have dinner together.
快递星期四就能到。
Kuàidì xīngqīsì jiù néng dào.
The delivery will arrive by Thursday.