Reticle
Beginner
The stencil plate used in the printing machine. It usually holds a few copies of the chip side by side.
Novice
The mask as it is loaded into the lithography machine. Its layout places one or more copies of the chip with test patterns, alignment marks and the scribe lines along which the wafer is later cut.
Expert
The reticle layout is built during mask data preparation. Its maximum size is set by the lithography tool, which caps the size of a single die.
Explained in GDS & tapeout (Design Flow).
See also: Photomask, Mask data preparation (MDP).