Return

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ROBLOX Wiki

Lua Pil

I'd say return is, simply put, the function is giving some thing(s) back. The provided links, though, go more in-depth if you would like.

Example:

function FunctionThatReturns(x) -- Define our function and give it a parameter
	print(x) -- Print "x" to the output
	return x + 1 -- Give back x + 1
end
function FunctionThatDoesntReturn(x) -- Define our other function, also with a parameter
	print(x) -- Output "x"
end

print(FunctionThatReturns(5)) --> The function will print "5" then this will print "6"
print(FunctionThatDoesntReturn(11)) --> The function will print "11" then this will print nothing, as nothing was given back.