What does 一整天 (yī zhěng tiān) mean?

一yī整zhěng天tiān means:

  • all day long
  • all day
  • whole day long

整zhěng means “whole” or “entire”, while 天tiān means day, so put together 整zhěng天tiān means “all day” or “entire day”. By itself 一yī means “one”, so by appending this to 整zhěng天tiān is to say “one entire day” 一yī整zhěng天tiān, as opposed to “all day” or “entire day” 整zhěng天tiān.

一整天 examples:

昨zuó天tiān一yī整zhěng天tiān都dōu在zài下xià雨yǔ
zuó​tiān yī zhěng​tiān dōu zài xià​yǔ

Yesterday it rained all day

Breakdown:

  • yesterday 昨zuó天tiān
  • all day 一yī整zhěng天tiān
  • all in the process of 都dōu在zài
  • raining 下xià雨yǔ

他tā今jīn天tiān一yī整zhěng天tiān对duì谁shéi都dōu是shì又yòu吼hǒu又yòu叫jiào的de
tā jīn​tiān yī zhěng​tiān duì shéi dōu shì yòu hǒu yòu jiào de

He’s in a bad mood. He’s been yelling at everybody all day.

Breakdown:

  • he 他tā
  • today 今jīn天tiān
  • all day long 一yī整zhěng天tiān
  • towards whomever 对duì谁shéi
  • (all) are 都dōu是shì
  • yelling and screaming 又yòu吼hǒu又yòu叫jiào的de

在zài那nà里li他tā要yào坐zuò上shàng一yī整zhěng天tiān
zài nà​li tā yào zuò shàng yī zhěng​tiān

He sat there all day

Breakdown:

  • located 在zài
  • there 那nà里li
  • he 他tā
  • wanted 要yào
  • sit down 坐zuò上shàng
  • all day 一yī整zhěng天tiān

我wǒ一yī整zhěng天tiān都dōu不bù会huì在zài办bàn公gōng室shì
I will be out of the office all day

Breakdown:

  • I 我wǒ
  • all day 一yī整zhěng天tiān
  • entirely 都dōu
  • not able / not likely 不bù会huì
  • (to be) located at 在zài
  • the office 办bàn公gōng室shì

我wǒ能néng睡shuì一yī整zhěng天tiān
I could run all day

Breakdown:

  • I’m 我wǒ
  • able to 能néng
  • sleep 睡shuì
  • all day 一yī整zhěng天tiān

我wǒ可kě以yǐ跑pǎo一yī整zhěng天tiān
I could run all day

Breakdown:

  • I 我wǒ可kě以yǐ跑pǎo一yī整zhěng天tiān
  • could / able to 我wǒ可kě以yǐ跑pǎo一yī整zhěng天tiān
  • run 我wǒ可kě以yǐ跑pǎo一yī整zhěng天tiān
  • all day 我wǒ可kě以yǐ跑pǎo一yī整zhěng天tiān