(Greek > Latin: a cave, a cavern, a grotto)
2. Another term for a speleologist.
3. Etymology: "A cave bug; one who explores caves as a hobby", 1942, formed from obsolete spelunk "cave, cavern" (c.1300), from Old French spelunque, from Latin spelunca, "a cave, cavern, grotto", from Greek spelynx (genitive spelyngos). An adjective, speluncar "of a cave" is recorded from 1855.
2. A sport which involves climbing into and around underground caves.
Caves have been explored out of necessity for thousands of years, but only in the last century or two has the activity become a sport.
In recent decades spelunking has changed considerably because modern-protective wear and equipment have improved the safety factors.
It has recently come to be known as an "extreme sport" by some; although it is not commonly considered as such by its participants.
Urban spelunking is also commonly referred to as "infiltration", although some people consider infiltration to be more closely associated with the exploration of active or inhabited sites.
In the U.S.A., it may also be referred to as "draining" (when exploring drains) "urban exploration", and "urban caving."