General:

• Cache – A box or container that contains, at the very least, a logbook.
• Muggle – A non-geocacher.
• Muggled – Being caught by a non-geocacher while retrieving/replacing a cache; also, a muggled cache has been removed or vandalized by a non-geocacher, usually out of misunderstanding or lack of knowledge.
• Smiley – A cache find. Refers to the "smiley-face" icon attached to "Found It" logs on some listing sites.
• CITO – (Cache In Trash Out) Picking up trash on the hunt.
• CO – (Cache Owner) The person who is responsible for maintaining a cache, usually the person who hid it.
• DNF – (Did Not Find) Did not find the cache container being searched for.
• FTF – (First To Find) The first person to find a cache container; less commonly one may see STF (second to find, or TTF, third to find).
• FTL – (First To Log) The first person to log the find of a cache container online.
• GPS – Short for Global Positioning System, also occasionally refers to the receiver itself.
• GPSr – Short for GPS receiver.

Logging a hunt:

• TFTC – (Thanks For The Cache) This is often used at the end of logs to thank the cache owner.

Location description or hint:

• GZ – (Ground Zero or Geo-zone) refers to the general area in which a cache is hidden.