Day

一天

yītiān

(part of a day period which one spends at one's job, school, etc.)

天

tiān

(period of 24 hours)

天

tiān

(period from midnight to the following midnight)

日

rì

(period of 24 hours)

白天

báitiān

(period between sunrise and sunset)

白天

báitiān

(part of a day period which one spends at one's job, school, etc.)

白晝 /白昼

báizhòu

(part of a day period which one spends at one's job, school, etc.)