Thursday, the fourth day of the week.
木曜日に会議があるので、その日だけ出社します。
I have a meeting on Thursday, so I'll come to the office only that day.
今度の木曜日は祝日で電車が混むでしょう。
Next Thursday is a holiday, so trains will probably be crowded.
木曜は英会話教室に通っています。
I attend an English conversation class on Thursdays.