In days when some scholars used to show
off what Greek they know, or had found
in a dictionary, almost every kind of
line showing constant values was given
a distinct name: some have flourished
in limited fields, e.g. isotherm (temperature),
isohyet (rainfall), isobath (depth).
Some failed to get off the ground, e.g.
isonoet (lines of equal IQ), found I believe
only in one study of IQ patterns in Tasmania.
Few students can escape intermediate microeconomics (or beyond)
without learning about "isoquants": the set of combinations of factor
inputs that generate the same level (quantity) of output for a given
production function.
