1.NounA hyperbolic function that is the analogue of the cosine function for hyperbolic spaces, taking in a hyperbolic angle as an argument and returning the y-coordinate for the corresponding point on the unit hyperbola, symbolically represented as:
"
cosh
(
x
)
=
1
2
(
e
x
+
e
−
x
)
{\displaystyle \cosh(x)={\tfrac {1}{2}}(e^{x}+e^{-x})}
."