Hangul syllable nyeon

It counts years in Korean.

5년 후 means “after five years.” Do I put a space before 년? Separate it from Korean number words; an Arabic numeral may join it, as in 5년.

Why is 년 sometimes 연?

연 is the word-initial form. 연도 means “calendar year.” The Korean word 년 comes from Chinese 年, but its Hangul spelling has a separate shape.

On oracle bones from the Shang period (animal bones and turtle shells used for divination), 年 pictured a person carrying grain and meant a good harvest; its calendar-year sense developed later. Before Hangul, Chinese characters were used to write Korean. Hangul, the Korean alphabet, was created in 1443; its explanatory book appeared in 1446.