Origin: Latin suffix -al
Astronomical has 3 different meanings across 1 category:
inconceivably large
"The cost of the new telescope project is astronomical, far exceeding what anyone expected to spend."
Of or relating to astronomy.
"The professor assigned an astronomical task that required us to calculate planetary orbits using a telescope."
In plain English: Astronomical means so huge that it is almost impossible to imagine how big something really is.
"The cost of the new house was astronomical."
The word astronomical entered English around 1550 via Middle French and Latin. It ultimately derives from the Ancient Greek term for "pertaining to stars."