semigrand

adjective2

1. •
   Of a piano: having a size intermediate between grand and baby grand.

   • An upright semi-grand piano near the door, flanked by two palms in pots, executed suddenly all by itself a valse tune with aggressive virtuosity. — 1906
2. •
   Pertaining to a distribution of species that holds the number of particles, pressure, and temperature fixed but allows mole fractions of species within a phase to fluctuate.

   • A cluster algorithm for Monte Carlo simulations in a semigrand ensemble was used. — 2015