1, an online buzzword, refers to something that touches you a lot, causes changes in emotional factors, and makes you more moved or sad.

2. Etymology: When it comes to the source of "old iron wears the heart", we have to mention the abstract TV of fighting fish. The audience in this live broadcast room is basically in the age group from teenagers to their twenties and thirties. They are very ostentatious and often send out barrage. One day, a group of children from Northeast China suddenly mixed into the live broadcast room, and many people posted a barrage of "Old Iron, Wear Heart", which quickly became popular on the Internet.