“SCCM” is not the official acronym for Systems Center Configuration Manager 2007. "ConfigMgr" is. “SCCM” is not owned as a trademark by Microsoft and therefore we really cannot use it. But I have noticed that many people have picked up on it and continue to use it. Even me, for instance: my main blog site is named SCCMNAP.Com.
I added the acronyms for each of the Microsoft System Center Products I found here.
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Microsoft Operations Manager—MOM Microsoft System Center Capacity Planner—SCCP Microsoft System Center Configuration Manager—ConfigMgr Microsoft System Center Data Protection Manager—SCDPM Microsoft System Center Essentials—SCE Microsoft System Center Operations Manager—OpsMgr Microsoft System Center Reporting Manager—SCRM Microsoft System Center Virtual Machine Manager—SCVMM Microsoft Systems Management Server—SMS