A grassroots technology can be an smart technical solution (a physical device, tool or machine) or a manufacturing, organizational or business process which can be easily replicated. It adresses a problem which might be a routine one or one caused by an emergency. A grassroots technology provides a cheap, fast-acting and decentral solution. Worldwide, people develop such simple tools and ways to improve their living, working and environmental conditions. Often these tools and ways are only locally known and used.
Another word for "grassroots" could be "appropriate". Of course, every technology has to make sense in the specific context. This concerns among other things the scale or dimension of its application, climatic conditions, affordability, epidemiological situation, public acceptance, availability and cost of construction materials, mechanical and electrical equipment, et cetera. Always, grassroots technologies are low cost technologies affordable to people to help themselves.
"Low tech" and "low cost" are related terms too. To define a little bit the focus of GrassrootsWiki here are some characteristics of grassroots technologies from our point of view: