ALR = Additional Logging Requirement
BYOP = Bring Your Own Pen
CITO = Cache In, Trash Out (event type)
CO = Cache Owner
CSI = Cache Satisfaction Index. Generally with a number 0 (being bad) to 5 (Excellent)
D5 = geocache with very high difficulty rating (eg. needing a Bex and a lie down 😉 )
DNF = Did Not Find
DOP = Dilution of precision, describes the geometric strength of satellite configuration
D/T = Difficulty/Terrain rating.
EPE = Estimated Position Error – a measurement of horizontal position error in feet or meters based upon a variety of factors including DOP and satellite signal quality.
FLTF = full log to follow
FTF = First to Find. (Often wrapped as {FTF} to aid in auto stats gathering)
GC = Geocache, also the website/cache Also GeoCoin.
GCA = Geocaching Australia, website/cache.
GPS = Global Positioning System
GPSr = GPS Receiver
GPX = file type used GPSs and apps for cache data exchange
GSAK = Geocaching Swiss Army Knife utility
GZ = Ground Zero – where the cache was (or rather should be) located/found.
LTF = Log to Follow
NINO = Nothing In, Nothing Out
P81 = Project 81 – challenge to find caches to complete the whole 81 D/T matrix/grid.
P366 = Project 366 – challenge to complete the whole 366 day calendar with GC finds (doesn’t have to be the SAME year).
PAF = Phone A Friend – often employed trying to avoid a DNF!
PM = Private Message (eg email, off-forum message, etc)
POI = Point of Interest – as the name says…
QR = Quick Response code (a square matrix-barcode)
SPOR = Suspicious Pile of Rocks
STF = Second to Find.
T5 = geocache with very high terrain rating (eg. needing a boat, scuba or climbing gear)
TB = Travel Bug trackable tag (also used for other similar trackables/tags)
TFTC = Thanks for the Cache (recommend never to be used alone as a log entry!)
TFTE = Thanks for the Event (recommend never to be used alone as a log entry!)
TFTH = Thanks For The Hunt/Hide
TNLNSL = Took Nothing, Left Nothing, Signed Log.
TOTT = Tools Of The Trade
TTF = Third to Find.
UPS = Unusual Pile of Sticks/Stones
WP = Waypoint – location of a stage of a multi-cache or similar along the route to GZ