The meaning of the word "service"

I became confused when I heard the word "Service" used with these agencies:
Internal Revenue 'Service' 
U.S. Postal 'Service' 
Telephone 'Service' 
Cable TV 'Service'
Civil 'Service' 
State, City, County & Public 'Service'
Customer 'Service' 
This is not what I thought 'Service' meant.

But today, I overheard two farmers talking, and one of them said he had hired a bull to 'Service' a few cows.

BAM!!!  It all came into focus. Now I understand what all those agencies are doing.

I hope that you are now just as enlightened as I am.