Meaning of dāng nián:
当年
in those days; back then; in those years; to be in the prime of life
Nà shì yī duàn huīhuáng de rìzi, wǒmen zhìjīn réng huáiniàn dāngnián.
那是一段辉煌的日子,我们至今仍怀念当年。
Those were glorious days, we still miss those years.
Tā zài dāng nián shì yī gè zhù míng de yùn dòng yuán.
他在当年是一个著名的运动员。
He was a famous athlete in his prime.
that very same year
Wǒmen zài dāngnián zhōngyú shíxiànle zhège mèngxiǎng.
我们在当年终于实现了这个梦想。
We finally achieved this dream that very same year.