This is the 8951st most frequent Japanese word.
水曜日
Wednesday.
Time marker indicating when the event 'going to the library' occurs.
水曜日に図書館に行きます。
I will go to the library on Wednesday.
Subject of the sentence describing the day's condition 'busy'.
水曜日は忙しいです。
Wednesday is busy.
Part of a phrase specifying 'next Wednesday' as the reference for the event 'holiday'.