I've Always Been Confused When I Heard The Word Service...

...used in these contexts:

Internal Revenue SERVICE
US Postal SERVICE
Telephone SERVICE
Cable TV SERVICE
Civil SERVICE
State, City, County and Public SERVICE
Customer SERVICE


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

BAM!  It all came into focus. Now I understand what all this SERVICE really is!

H/t To JW