IPA: /ɪkˈspæns/
KK: /ɪkˈspæns/
A large and open area of land, sky, or surface that stretches out in all directions.
The vast expanse of the ocean was breathtaking.
Expanse is derived from "ex-" (meaning out) and "pandere" (meaning to spread). The word describes something that spreads out or extends over a wide area.
Imagine something that spreads out 'outward' ('ex-') — that's why expanse means a wide area that extends out.