Usage note
同一意思是完全一样，没有不同。
Tóngyī yìsi shì wánquán yīyàng, méiyǒu bùtóng.
Identical means exactly the same, with no difference.
Context note
双胞胎穿着同一件衣服，看起来一模一样。
Shuāngbāotāi chuānzhe tóngyī jiàn yīfu, kàn qǐlái yīmú yīyàng.
Twins wearing the identical clothes look exactly the same.
5 examples
我们住在同一栋楼里。
wǒ men zhù zài tóng yí dòng lóu lǐ。
We live in the identical building.
他们俩有同一本书。
tā men liǎ yǒu tóng yì běn shū。
They both have the identical book.
同一时间，大家都在上课。
tóng yì shí jiān， dà jiā dōu zài shàng kè。
At the identical time, everyone is in class.
这两只铅笔是同一颜色。
zhè liǎng zhī qiān bǐ shì tóng yì yán sè。
These two pencils are the identical color.
我们去了同一家商店。
wǒ men qù le tóng yì jiā shāng diàn。
We went to the identical store.
5 mini stories
小红和小蓝穿了同一双袜子。
xiǎo hóng hé xiǎo lán chuān le tóng yì shuāng wà zi。
Xiao Hong and Xiao Lan wore the identical pair of socks.
他们笑着发现是同一双。
tā men xiào zhe fā xiàn shì tóng yì shuāng。
They laughed and found it was the identical pair.
小明和小华在同一班级学习。
xiǎo míng hé xiǎo huá zài tóng yì bān jí xué xí。
Xiao Ming and Xiao Hua study in the identical class.
他们每天一起做同一件事。
tā men měi tiān yì qǐ zuò tóng yí jiàn shì。
They do the identical thing together every day.
两朵花是同一颜色，非常漂亮。
liǎng duǒ huā shì tóng yì yán sè， fēi cháng piào liang。
The two flowers are the identical color, very beautiful.
Mini dialogue
一样的书包
A
你的书包和我的是同一款。
Nǐ de shūbāo hé wǒ de shì tóng yī kuǎn.
Your backpack is the same style as mine.
B
真的吗？好巧啊！
Zhēn de ma? Hǎo qiǎo a!
Really? What a coincidence!
同一本书
A
我们看的是同一本书。
Wǒmen kàn de shì tóng yī běn shū.
We are reading the same book.
B
太好了，我们可以一起讨论。
Tài hǎo le, wǒmen kěyǐ yīqǐ tǎolùn.
Great, we can discuss it together.
Related words and contrasts
similar
相同
xiāng tóng
same
Both mean identical or the same.
opposite
不同
bù tóng
different
Opposite of identical.