...It doesn't just mean that. Boss has more than one way to be used, even just as a Noun. Merriam-Webster changed its definition page formatting. Look at the 2nd option for "Boss (Noun)" in the entry-selection thingy.
1
: a person who exercises control or authority; specifically : one who directs or supervises workers
2
: a politician who controls votes in a party organization or dictates appointments or legislative measures
Origin of BOSS
Dutch baas master
First Known Use: 1653
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