Usage note
半天表示一天的一半时间，也可以用来形容花了很长时间。
bàn tiān biǎo shì yī tiān de yī bàn shí jiān, yě kě yǐ yòng lái xíng róng huā le hěn cháng shí jiān.
This word means half a day, and it can also be used to say that something took a long time.
Context note
半天这个词用来表示大约一个上午或一个下午的时间，也可以形容感觉时间很长。
Bàn tiān zhè ge cí yòng lái biǎo shì dà yuē yī gè shàng wǔ huò yī gè xià wǔ de shí jiān, yě kě yǐ xíng róng gǎn jué shí jiān hěn cháng.
This word is used to talk about a period of roughly half a day, like a morning or an afternoon. It can also describe when something feels like it takes a long time.
5 examples
我们今天工作了半天。
wǒ men jīn tiān gōng zuò le bàn tiān。
We worked for half a day today.
我每天锻炼身体半天。
wǒ měi tiān duàn liàn shēn tǐ bàn tiān。
I exercise my body for half a day every day.
他们昨天玩了一整天，今天只玩了半天。
tā men zuó tiān wán le yì zhěng tiān， jīn tiān zhī wán le bàn tiān。
They played all day yesterday, but only half a day today.
这个项目需要两天时间完成，第一天我们完成了半天的工作量。
zhè gè xiàng mù xū yào liǎng tiān shí jiān wán chéng， dì yī tiān wǒ men wán chéng le bàn tiān de gōng zuò liàng。
This project needs two days to complete. On the first day, we completed half of the work load.
她每天早上跑步半小时，下午再跑半天。
tā měi tiān zǎo shàng pǎo bù bàn xiǎo shí， xià wǔ zài pǎo bàn tiān。
She runs for half an hour in the morning and then runs for another half a day in the afternoon.
5 mini stories
小明今天上午在学校学习了半天，下午回家写作业。
xiǎo míng jīn tiān shàng wǔ zài xué xiào xué xí le bàn tiān， xià wǔ huí jiā xiě zuò yè。
Xiaoming studied for half a day at school this morning, and did his homework after school.
妈妈说周末要带我去公园玩半天。
mā ma shuō zhōu mò yào dài wǒ qù gōng yuán wán bàn tiān。
Mom said she would take me to the park to play for half a day on the weekend.
爸爸每天早上跑步半小时，下午再跑半天。
bà ba měi tiān zǎo shàng pǎo bù bàn xiǎo shí， xià wǔ zài pǎo bàn tiān。
Dad runs for half an hour in the morning and then runs for another half a day in the afternoon.
我们昨天开会开了半天，讨论了很多问题。
wǒ men zuó tiān kāi huì kāi le bàn tiān， tǎo lùn le hěn duō wèn tí。
We had a meeting for half a day yesterday, discussing many issues.
姐姐每天早上做家务半小时，下午再做半天。
jiě jie měi tiān zǎo shàng zuò jiā wù bàn xiǎo shí， xià wǔ zài zuò bàn tiān。
My sister does housework for half an hour in the morning and then another half a day in the afternoon.
Mini dialogue
等了半天
A
你怎么现在才来？
Nǐ zěnme xiànzài cái lái?
Why are you only coming now?
B
对不起，公交车让我等了半天。
Duìbuqǐ, gōngjiāo chē ràng wǒ děng le bàn tiān.
Sorry, I waited for the bus for half a day.
玩了半天
A
你们上午做了什么？
Nǐmen shàngwǔ zuò le shénme?
What did you do this morning?
B
我们在公园玩了半天。
Wǒmen zài gōngyuán wán le bàn tiān.
We played in the park for half a day.
Related words and contrasts
similar
半天
bàn tiān
a long while
半天 can also mean 'a long time', not just exactly half a day.
contrast
一天
yī tiān
one day
半天 is half a day; 一天 is a full day.