These are special term used by both Tiled and libTMX, or only the latter.

Application Binary Interface, an interface between two binary program modules, here between your software and the compiled version of libTMX. See the ABI page on wikipedia.
Application Programming Interface, in C, a set of structure and function definitions used to build new sofware using existing material. See the API page on wikipedia.
A texture atlas is a set of textures assembled in a single image to reduce the overhead of loading several images from non volatile storage (hard drives, CD, …) and to optimize the usage of VRAM.

An entry of a tile layer, the content of a cell is the GID, possibly tainted with a tile flip flag.

See layer_content.gids.


Global tile Identifier, uniquely identifies a tile at map scope.

To compute the GID from a LID in a given map: int32_t GID = tileset_list->firstgid + tile->id;.


GID=0 (zero) is a special GID which means that this cell is empty!

See the Working with Layers page on Tiled documentation.

Local tile Identifier, uniquely identifies a tile at tileset scope.


Linked List
A linear collection of data elements, each element points to the next. See the wikipedia page on linked lists.
See the Working with Objects page on Tiled documentation.
Name given to images meant to be used in video games, usually given to images once they are loaded in memory or in the VRAM.
The atomic element that constitute tile layers and tilesets, usually a small square image.
A set of tiles, in Tiled tilesets are usually external resources, hence they have a scope that is different from the scope of the map, explaining the GID and LID paradigm. Tilesets can be based on a single image (an atlas) or a collection of images (one for each tile).
Tile Map XML map format used by Tiled, it is based on the XML format.
A data structure of nodes, starting at a root node, each nodes may have zero, one or several child nodes. See the wikipedia page on trees.
Tile Set XML tileset format used by Tiled, it is based on the XML format.
Template XML template format used by Tiled, it is based on the XML format.
Video RAM, name of the volatile random access memory attributed to the GPU.
Extensible Markup Language is the markup language used by the TMX map format. See the XML specification.