Inbox: "Service"

I became confused when I heard these terms with reference to the word "service:"

Internal Revenue Service
US Postal Service
Telephone Service
Cable Service
Civil Service
State, City and 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, then...BAM!  It all came into focus.  Now I understand what all those "service" agencies are doing to us.

I hope you are as enlightened as I am.