The technological and industrial history of Canada encompasses the country's development in the areas of transportation, communication, energy, materials, public works, public services (health care), domestic/consumer and defense technologies. Most technologies diffused in Canada came from other places; only a small number actually originated in Canada. For more about those with a Canadian origin see Invention in Canada. The terms chosen for the "age" described below are both literal and metaphorical. They describe the technology that dominated the period of time in question but are also representative of a large number of other technologies introduced during the same period. Also of note is the fact that the period of diffusion of a technology can begin modestly and can extend well beyond the "age" of its introduction. To maintain continuity, the treatment of its diffusion is dealt with in the context of its dominant "age".