According to Cambridge Dictionary
the mixing of different ideas, influences, or things to make a whole that is different, or new
Is there any related noun that shares the same root synth for the one that "executes" the mix, the agent that creates it. If not, what is the noun that applies to that agent?
Note: synthesizer looked promising but it was a mirage [No pun intended with the Ensoniq Mirage synthesizer]
An electronic musical instrument, typically operated by a keyboard, producing a wide variety of sounds by generating and combining signals of different frequencies
EDITED: After @JavaLatte's answer, let me narrow the context. Let's say that we are talking about computing. If we have a program that calculates D as
A + B + C = D
or the more generic
func(A, B, C) = D
What's the name that you will use for the program? DAggregator does not sound good, nor DCalculator. I love DSynthesizer but the word has been "hijacked" as pointed by @JavaLatte.