A synth or soft synth which provides internal signal routing capabilities equivalent to (or nearly so) a modular synthesizer. A virtual modular architecture goes beyond matrix routing in that generally any signal that is output by one function of the synth can be routed to any signal input in any other part of the synth that is compatible, and the total number of simultaneous routings is limited only by the available input points.
Native Instruments' Reaktor is a well known example of a soft synth that implements a virtual modular concept. The Solaris is a hardware synth built around a virtual modular architecture.