What does a speleologist explore?

I wonder what the etymological roots of this word are?

Otherwise called “spelunkers

I had the privilege of going on one cave crawl with professional cave mappers. they worked exclusively in what is known as Jewel Cave in South Dakota.

Dixienormus, watch your language.

arohanui, British English is standard English. They invented it, Americans bastardised it.

it's standard English, not British English.