  A clear understanding of chirality in spin-active electronic states is
discussed in order to address confusions about chiral effects recently
discovered in materials science. Electronic toroidal monopole $G_0$ can serve
as a measure of chirality in this categorization, which can be clearly related
to the chiral density operator in the Dirac equation. We extend the concepts of
chirality not only to those of materials but also to those of physical fields,
and to material-field composites. Additionally, we illustrate specific examples
from physics and chemistry that demonstrate the process of acquiring chirality
through the combination of seemingly achiral degrees of freedom, which we term
the emergence of chirality. Interference among multiple chiralities exhibiting
phenomena specific to handedness is also discussed.
