This is the 16th most frequent Japanese word.
年
"Year."
Here, '年' is used as a measure of time duration, expressed as '18年' to indicate the span of years.
彼は18年もこの会社で働いています。
He has been working at this company for as long as 18 years.
In this example, '年' is used in '年間' to represent the duration of studying, with '6年間' specifying a period of six years.
日本の小学校では6年間勉強します。
In Japanese elementary schools, students study for six years.
In this sentence, '年' is used in the word '今年' (this year), indicating a specific year relative to the current year.