This is the 1069th most frequent Japanese word.
書き
"書き" means "writing" or "written text."
The verb '書きます' (kakimasu) here means 'to write,' and it is used in its polite, present tense form.
彼は毎日の日記を書きます。
He writes in his diary every day.
The term '書き終えた' (kaki oeta) integrates '書き' with '終えた,' forming a construction that describes the action of completing writing.
書き終えたレポートを先生に提出しました。
I submitted the completed report to the teacher.
'書き方' (kakikata) combines '書き' with '方,' meaning 'the way of writing' or 'writing style.'