牢（láo）

 
字形：
古体“牢”字外部“宀”是屋顶，表示牲畜的圈，中间是“牛”字，代表牲畜，整个字像牲畜被关在圈里的   形状。古时牢是养牲畜的地方，有成语“亡羊补牢”，意思是，羊丢了，赶快修补羊圈，还不晚。后来， “牢”的意思由关牲畜的地方引申为关人的地方，即监狱。
The exterior part of the ancient form of the character "牢" is like the fence surrounding the livestock, and its middle part is "牛" representing livestock. The whole character indicates the livestock enclosed in fences. In the ancient time, "牢" was where livestock were raised. There is an idiom "亡羊补牢" means it is still not too late if one mends the fold quickly after the sheep have been stolen. Later, the meaning of "牢" extended to refer to the places where people were kept, i.e.  prisons. Now, the common meaning of "牢" is prison.
 
字义：
prison
 
组词：
牢房（láofáng）：prison
坐牢（zuòláo）：be in prison
牢固（láogù）：firm
牢记（láojì）：remember well
牢骚（láosāo）：complaint
牢靠（láokào）：reliable
 
例句：
Tā yīnwèi tōu dōngxi ér zuòláo le.
1、他因为偷东西而坐牢了。
He's in prison for pinching goods.
Wǒ shìzhe bǎ tā shuō de huà láojì zài xīnli.
2、 我试着把她说的话牢记在心里。
I tried to fix her words in my mind.
Yóuyú méiyǒu zúgòu de zījīn, zhè jiā qǐyè de jīchǔ bù láokào, bùjiǔ jiù pòchǎn le.
3、由于没有足够的资金，这家企业的基础不牢靠，不久就破产了。
The business was built on sand because it has insufficient capital, and it soon failed.