Definitions

Open Firmware Device Tree - Data structure used by Open Firmware to describing hardware.
Flattened Device Tree (FDT) - Same data as in the Open Firmware device tree, either created by hand or exported to
Device Tree Source (.dts) - ASCII text representation of device tree data; This is the human readable source form.
Device Tree Blob (.dtb) - Packed representation of device tree data; readable by operating systems and firmware.
Device Tree Compiler (dtc) - tool for compiling .dts files into the .dtb form.
binding - Documentation about how to describe a device in the device tree