The second item in a series is the one that you count as number two.
第二 • ...the second day of his visit to Delhi. …他访问德里的第二天。
Seconds are goods that are sold cheaply in stores because they have slight faults.
次品
If you second a proposal in a meeting or debate, you formally express your agreement with it so that it can then be discussed or voted on.
附议
You say second when you want to make a second point or give a second reason for something.
第二; 其次