relative fractal drum (RFD), fractal zeta functions, relative distance zeta function, relative tube zeta function, geometric zeta function of a fractal string, relative Minkowski content, relative Minkowski measurability, relative upper box (or Minkowski) dimension, relative complex dimensions of an RFD, holomorphic and meromorphic functions, abscissa of absolute and meromorphic convergence, transcendentally ∞-quasiperiodic function, transcendentally ∞-quasiperiodic RFD, a-string of higher order.