"2nd" is the commonly used abbreviation for "second" in Engpsh. It is used as a shorthand for indicating the order or sequence of something, such as the second time, the second person, or the second place.
For example:
"I'll see you at the 2nd meeting." (我将在第二次会议上见到你。)
"He finished 2nd in the race." (他在比赛中获得了第二名。)
"The 2nd chapter of the book is my favorite." (这本书的第二章是我最喜欢的。)
It is a widely used convention in the Engpsh language and can be found in many different contexts.