QEMU (short for Quick EMUlator)[2] is a free and open-source emulator that performs hardware virtualization.
QEMU is a hosted virtual machine monitor: it emulates the machine’s processor through dynamic binary translation and provides a set of different hardware and device models for the machine, enabling it to run a variety of guest operating systems. It also can be used with KVM to run virtual machines at near-native speed (by taking advantage of hardware extensions such as Intel VT-x). QEMU can also do emulation for user-level processes, allowing applications compiled for one architecture to run on another.[3]
Full-system emulation – Run operating systems for any machine, on any supported architecture
User-mode emulation – Run programs for another Linux/BSD target, on any supported architecture
Source: QEMU

E-Maculation: All About Macintosh Emulation (Site updated October 22, 2018) Welcome E-Maculation is dedicated to emulation of the classic Macintosh computer in Mac OS X, Windows and Linux. This is possible through the use of emulators such as SheepShaver, Basilisk II, Mini vMac, Qemu and
PearPC is an architecture-independent PowerPC platform emulator capable of running most PowerPC operating systems.
Home page of the SheepShaver Macintosh emulator