日
day; sun
rì
What does 日 mean?
日 (rì) means both 'day' and 'sun' — it is the pictograph the character started as. In modern Mandarin, bare 日 has largely been replaced in speech by 天 (tiān, 'day') and 太阳 (tàiyáng, 'sun'); you will rarely hear someone say 今日 instead of 今天 in casual conversation. Where 日 still rules is in writing dates and in two-character compounds. Dates always use 日 in formal writing: 5月16日 (May 16). The character also locks into 生日 (shēngrì, 'birthday'), 日记 (rìjì, 'diary'), 星期日 (xīngqīrì, 'Sunday'), 日本 (Rìběn, 'Japan' — literally 'sun's origin'), and 日常 (rìcháng, 'daily'). When you see 日 standing alone, think 'written / formal,' and switch to 天 when speaking.
Note: Written / formal. In spoken Mandarin, 天 (tiān) is the everyday word for 'day.' 日 survives in dates, formal writing, and fixed compounds (生日, 日记, 星期日).
Character breakdown
sun; day
Memory hook: 日 started as a picture of the sun — a circle with a dot. The dot is now a stroke, but the meaning 'sun / day' stuck.
Example sentences
我的生日是五月十六日。
Wǒ de shēngrì shì wǔ yuè shíliù rì.
My birthday is May 16th.
neutral
今天是星期日。
Jīntiān shì xīngqīrì.
Today is Sunday.
neutral
他来自日本。
Tā láizì Rìběn.
He's from Japan.
neutral
她每天写日记。
Tā měi tiān xiě rìjì.
She writes in her diary every day.
neutral
Common phrases with 日
Synonyms
天 is the spoken word for 'day' — 今天 ('today'), 明天 ('tomorrow'), 三天 ('three days'). Use 日 in dates and formal writing; use 天 in speech and when counting days.
太阳 is the everyday word for 'the sun.' 日 only means the sun in literary contexts (日出 'sunrise,' 日落 'sunset'). In conversation, say 太阳出来了, not 日出来了.
Don't confuse 日 with
目 ('eye') looks like 日 with an extra horizontal stroke inside. 日 has two strokes inside (or two segments); 目 has three. Different word, different meaning.
白 ('white') is 日 with a small stroke on top. The components share a root visually but mean different things.
天 is the spoken counterpart for 'day' and also means 'sky / heaven.' For dates 日; for counting days or in speech 天.