IPA: /ˌæstrəˈnɒmɪkəl/
KK: /æstrəˈnɑmɪkəl/
Relating to very large sizes or amounts, often used to describe something that is extremely great or immense.
The costs of the project were astronomical, far exceeding our initial budget.
Astronomical → It is formed from "astro-" (from Greek "astron", meaning star) and "nomos" (meaning law or arrangement). The word "astronomical" refers to something related to the laws or arrangements of stars, often implying vastness or immensity.
Think of 'stars' ('astro-') and 'laws' ('nomos') to remember that 'astronomical' relates to the vastness of the stars.