This is the 220th most frequent Japanese word.
機
"機" (ki) means machine, opportunity, or mechanism.
Here, '機' is used as part of the word '機械' (kikai), meaning 'machine'.
機械が故障しました。
The machine broke down.
In this example, '機' is included in '飛行機' (hikouki), meaning 'airplane'.
飛行機が東京から出発します。
The airplane departs from Tokyo.
In this sentence, '機' is incorporated in the word '機会' (kikai), which means 'opportunity'.