The range of colours covered by one name can be very wide. The borderlines between colours with different names are vague and variable. Pink , for example, can mean anything from light red to pale magenta and beyond.
If someone says
red they could easily mean
or anything in between.
is frequently called blue but it’s also called green in different contexts,
particularly if it’s a darker cyan.
Normally this doesn’t matter, but…
The three diagrams are all taken from one
second two are even on the same page—but
the author gives different names to the identical red in different diagrams!
She calls it
red when it’s a
primary color of white light or a
orange when it’s a
and then uses
orange to mean a different colour in the middle diagram!
This is not an isolated case.
Many contemporary texts on painters’ colours make similarly confusing shifts of meaning.
Even in scientific texts you may find a shift from
when describing the complementary pair