training refers to the acquisition of UX-related knowledge, skills, and competencies
The term training refers to the acquisition of knowledge, skills, and competencies as a result of the teaching of vocational or practical skills and knowledge that relate to specific useful competencies. Training has specific goals of improving one's capability, capacity, and performance.
Questions having the training tag refers to training in a general user experience context. Training of the users instead uses the end-user-training tag.
Reference: http://en.wikipedia.org/wiki/Training
