HSK 5 HSK C4/V4
Correct

阵

/ zhèn / 
Strokes

Definition

disposition of troops/wave/spate/burst/spell/short period of time/classifier for events or states of short duration

Example

As a Noun

battle array/formation

1
Yánzhènyǐdāi
严阵以待

be completely ready in battle array

2
Bǎi
摆
le
了
gè
个
yī
一
zì
字
cháng
长
shé
蛇
zhèn
阵

deploy the troops in a long single-file line

As a Noun

position; front; battle

3
Shàngzhèn
上阵
shādí
杀敌

go to battle to fight the enemy