则
zé
(literary) (conjunction used to express contrast with a previous clause) but; then
(bound form) standard; norm; (bound form) principle; (literary) to imitate; to follow; classifier for written items
This is a classical Chinese function word — its meaning is grammatical.
他努力学习，则成绩自然会提高。
tā nǔ lì xué xí， zé chéng jì zì rán huì tí gāo。
He studies hard, then his grades will naturally improve.
姐姐喜欢安静，弟弟则喜欢热闹。
jiě jie xǐ huān ān jìng， dì di zé xǐ huān rè nào。
The older sister likes quiet, but the younger brother likes noise.
Words with 则
通则
tōng zé
general rule
遇强则强
yù qiáng zé qiáng
tough adversaries make you stronger
附则
fù zé
supplementary provision
虽则
suī zé
nevertheless
一中原则
yī zhōng yuán zé
One-China principle, the official doctrine that Taiwan is a province of China
一则
yī zé
on the one hand
一则以喜，一则以忧
yī zé yǐ xǐ , yī zé yǐ yōu
happy on the one hand, but worried on the other
一般原则
yī bān yuán zé
general principle
三人行，则必有我师
sān rén xíng , zé bì yǒu wǒ shī
If three walk together, one of them can teach me sth (Confucius)
不平则鸣
bù píng zé míng
where there is injustice, there will be an outcry
不规则
bù guī zé
irregular
不规则三角形
bù guī zé sān jiǎo xíng
scalene triangle (math.)