n.1. the relationship between the quantity or quality of output (goods created or services provided) and the input (time, materials, etc.) required to create it. 2. the capacity to produce goods and services having exchange value. Vocational rehabilitation programs often use the productivity of people with disabilities as a major measure of the effectiveness of the programs. 3. according to Roger Brown, one of the formal properties of all language, consisting of the ability to combine individual words to produce an unlimited number of sentences. See semanticity.