Geocrap = undesirable swaps
Geocoin = a coin or medallion-like trackable
Geocheck(er) = a website that can be used to check the calculated coordinates of GZ.
GeoMobile = Your method of Transport (eg car)
Geotrail = A path made by previous cachers that can lead to a cache.
GeoWidow = The spouse you don’t see much of anymore.
Geoyak = kayak – often useful for water-based T5 geocaches
GroundSpeak = The company that runs geocaching.com
Muggle = a non geocacher, usually can be found at GZ making life difficult!
Nano = tiny cache smaller than a Micro, but still classified as a Micro
Pathtags = collectible, round, metal dog-tag with inlayed enamel colors traded, given away or left in geocaches.
Trackable = generic term for objects that have a code number which allow them to be tracked through geocache visits (either grabbed, dropped or just visited).
Travel Bug = usually a military-style dog-tag trackable, but with some variations on the theme.
Unloved days = days since the last find on a cache
Challenge = A cache which asks you to meet certain goals / requirements to claim the find. eg, Find 100 traditional caches.