The concept of learning design arrived in the literature of technology for education in the late nineties and early 2000s with the idea that "designers and instructors need to choose for themselves the best mixture of behaviourist and constructivist learning experiences for their online courses". But the concept of learning design is probably as old as the concept of teaching. Learning design might be defined as "the description of the teaching-learning process that takes place in a unit of learning (eg, a course, a lesson or any other designed learning event)".
As summarized by Britain, learning design may be associated with:
The concept of learning design
The implementation of the concept made by learning design specifications like PALO, IMS Learning Design, LDL, SLD 2.0, etc...
The technical realisations around the implementation of the concept like TELOS, RELOAD LD-Author, etc...