settler

noun6

1. •
   Someone who settles in a new location; especially one who takes up residence in a previously uninhabited place.
2. •
   Someone who decides or settles something, such as a dispute.

   • The paddles were enormously versatile, serving as radio-antenna masts, shovels, ice prods, snow knives, and potential argument settlers—whoever had one in his hand at the time would win. — 1989
3. •
   (UK) The person in a betting shop who calculates the winnings.
4. •
   (informal) That which settles or finishes, such as a blow that decides a contest.
5. •
   A vessel, such as a tub, in which something, such as pulverized ore suspended in a liquid, is allowed to settle.

   • First, there will be little reaction in the settler so that the concentrations of soluble constituents in the recycle stream are the same as those in the bioreactor. — 2011
6. •
   A drink which settles the stomach, especially a bitter drink, often a nightcap.

   • [H]aving got out the rum bottle for a quiet “settler” just as the victim of his fascinations glided through the carefully adjusted door, he had been persuaded to go on drinking. — 1874