second
The Italian word 'secondo' is used similarly to the English 'second'. You can use it to represent order (as in 'first, second, third') or a unit of time. In terms of order, it would be as 'il secondo giorno' (the second day). As a unit of time, it remains 'un secondo' (a second).
I waited for a second.
In this context, 'secondo' is used to refer to a unit of time, more specifically, a second.
In my opinion, you should try cooking pasta.
Here 'secondo me' means 'in my opinion'. This phrase is commonly used in Italian to express personal opinions.
The second floor of the house is very large.
'Il secondo piano' means 'the second floor'. In Italian, cardinal numbers like 'secondo' are used to indicate the order of things.