Wednesday (abbreviated form for the weekday).
次の会議は水曜に予定されています。
The next meeting is scheduled for Wednesday.
水曜は図書館が混むので早めに行った方がいい。
The library gets crowded on Wednesdays, so it's better to go early.
学校では毎週水曜に部活動がある。
At school, club activities are held every Wednesday.