The 16th day of a month (used for dates).
次のミーティングは４月１６日です。
The next meeting is on April 16th.
１６日は図書館が休館ですか？
Is the library closed on the 16th?
飛行機は１６日に出発します。
The plane departs on the 16th.
A duration of sixteen days (a period lasting 16 days).
治療には１６日ほどかかると言われた。
I was told the treatment would take about sixteen days.
展示は１６日間開催される予定です。
The exhibition is scheduled to run for sixteen days.
彼は１６日連続で研修を受けた。
He attended training for sixteen consecutive days.