二
two
èr
What does 二 mean?
二 (èr) is the cardinal number 'two' in Mandarin. It's used for counting (一二三 yī èr sān), in phone numbers, room numbers, dates (二月 'February,' 二号 'the second'), and inside larger numbers (二十 'twenty,' 一百二十 'one hundred twenty'). The catch for learners: when 'two' is followed by a measure word and means 'two of something,' Chinese switches to 两 (liǎng). So 'two people' is 两个人 (liǎng ge rén), NOT 二个人. 二 stays put for ordinals, math, sequences, and labels. In informal slang, calling someone 二 also means 'silly' or 'naive,' but that meaning is unrelated to counting.
Note: Use 二 for the cardinal number two when counting, in phone numbers, in dates, and as part of larger numbers. Use 两 (liǎng) when 'two' is followed by a measure word — 两个 not 二个.
Character breakdown
two
Memory hook: Two horizontal lines = two. Easy.
Example sentences
一、二、三。
Yī, èr, sān.
One, two, three.
neutral
今天二月二号。
Jīntiān èr yuè èr hào.
Today is February 2nd.
neutral
我住在二楼。
Wǒ zhù zài èr lóu.
I live on the second floor.
spoken
他是第二名。
Tā shì dì èr míng.
He is in second place.
neutral
Common phrases with 二
Synonyms
两 means 'two' when followed by a measure word: 两个人, 两本书, 两杯水. 二 is used for counting numbers, ordinals, and inside larger numbers (二十). Saying 二个人 sounds wrong to native ears.
Don't confuse 二 with
Both mean 'two' but they split the work: 二 for math/counting/sequence; 两 for 'two of [thing]' with a measure word. 二楼 (the 2nd floor) but 两层楼 (two floors).
三 ('three') is just one more horizontal stroke than 二. Easy to misread when writing fast.