It's the unofficial title for the person/role above you at work, who takes the heat from management/owners.

This individual takes the shit, while the people below him/her are shielded from management's crap, trouble, finger pointing, etc..
"I'd like to apply for a higher paying, more senior position at the office, but I wouldn't want to end up being the shit umbrella for the whole department".
by BigE_from_New_York_City April 6, 2010
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