Oilfield Glossary is a mobile application designed for oilfield people. It allows you to easily search for a list of glossary terms about oil & gas exploration and production.

It's a great tool for your reference.

The app is free and it includes following features:

-Search for a glossary name or in the glossary description of common terminologies used in the industry
-Favourites
-Copy either glossary term or the description
-Works offline - no need for an internet connection
-Submit new glossary terms and description and help us to expand our comprehensive glossary

Examples include:

Christmas tree
The set of valves, spools and fittings connected to the top of a well to direct and control the flow of formation fluids from the well.

Gel strength
The shear stress measured at low shear rate after a mud has set quiescently for a period of time (10 seconds and 10 minutes in the standard API procedure, although measurements after 30 minutes or 16 hours may also be made).

Overshot
A downhole tool used in fishing operations to engage on the outside surface of a tube or tool. A grapple, or similar slip mechanism, on the overshot grips the fish, allowing application of tensile force and jarring action. If the fish cannot be removed, a release system within the overshot allows the overshot to be disengaged and retrieved.

Trip out
To remove the drillstring from the wellbore. Synonyms: POOH (Pull out of hole).

You can view the IADC Reporting Codes and find out what each code means. For example:

IADC Operational Codes - view the standard IADC operations codes used for your daily reports and get a full explanation what each code means. For example:

Code 6 : Trips - Trips in or out of the hole.
Code 7: Lubricate Rig - Normal lubrication and servicing of the rig.
Code 11: Wire Line Logs - Rigging up, tearing down and running logging equipment.
Code A: Perforating - Perforating casing, tubing or formation.