The 25th day of a month (used as a calendar date).
今月の２５日に会議があります。
There is a meeting on the 25th of this month.
家賃の支払いは毎月２５日です。
Rent is due on the 25th of every month.
１２月２５日にプレゼントを開けた。
I opened the present on December 25th.
A period of 25 days (duration). Often expressed as '25 days'.
彼は出張で２５日間海外に行っていた。
He was abroad on a business trip for 25 days.
この薬は２５日間続けて飲んでください。
Please take this medicine continuously for 25 days.
締め切りまで残り２５日しかない。
There are only 25 days left until the deadline.