Business Service vs Application Service vs Technical Service

Apologies as this may be way off the mark and if it is then any layman's help where my understanding has failed would be greatly appreciated.

We're trying to build a CMDB and part of this is the classification of Services different services used within the company. I've read a number of the forum posts and think at a very basic level i've grasped the concept (I hope)

* Business Service - would be a very high level grouping of application services for example "e-mail"
* Application Service - would be a collection of items which come together to provide the Business Service such as various software applications and hardware items "MS Outlook, MS Exchange, Windows Servers etc"
* Technical Service - would be the "Technical support" offered to support the various Application Services (potentially by 2nd/3rd line support teams)