１３日
じゅ
う
さ
ん
に
ち
Meanings
1
13th day of the month
Used to specify the 13th day of any month. Often appears in dates like １３日（じゅうさんにち）.
The meeting will be held on the 13th.
2
13 days
Used to express a duration of 13 days. Often followed by a counter or in phrases like １３日間.
This work took 13 days.
Usage patterns
- 〈時〉月１３日the 13th of [month]
The meeting will be held on May 13th.
- １３日間〈動詞〉to do something for a period of 13 days
I couldn't go outside for 13 days after being hospitalized.