Definition of quadratic:
part of speech: adjective
Pert.
to
or
containing
a
square.
Usage examples:

That
quadratic
problem
counted
thirty
credits.
Pauline Lester in "Marjorie Dean, High School Junior".

I
grasped
very
well
the
fact
that
a
plus
quantity
killed
a
minus
quantity
if
they
were
of
equal
value,
and
that
a
little
figure
two
by
the
side
of
a
letter
meant
its
square,
and
I
somehow
blundered
through
some
simple
equations,
but
when
Mr
Hasnip
lit
a
scholastic
fire
under
me,
and
began
to
force
on
bigger
mathematical
flowers
from
my
unhappy
soil
in
the
Doctor's
scholastic
hothouse,
I
began
to
feel
as
if
I
were
blighted,
and
as
if
quadratic
equations
were
instruments
of
torture
to
destroy
boys'
brains.
G. Manville Fenn in "Burr Junior".

The
doctrine
that
the
heavenly
bodies
were
moved
by
vortices
was
successively
modified,
so
that
it
came
to
coincide
in
its
results
with
the
doctrine
of
an
inverse
quadratic
centripetal
force....
John Stuart Mill in "A System Of Logic, Ratiocinative And Inductive (Vol. 1 of 2)".

Then
he
tried
to
do
the
sum
by
algebra,
by
simple
and
by
quadratic
equations,
by
trigonometry,
by
logarithms,
and
by
conic
sections.
Edith Nesbit in "The Book of Dragons".