This guidance, which is effective immediately, imposes a more rigorous definition of «specialized knowledge» as well as a mandatory wage requirement for some ICTs... (slaw.ca)
Savvy consumers understand the value of protecting the environment with a product that is effective and meets the most rigorous definitions of «natural» and «organic.» (petbusiness.com)
David Grier, a physics professor at New York University, told New Scientist that «there is no mathematically rigorous definition of life,» which makes it difficult to call these crystals «alive» [source: New Scientist Space]. (science.howstuffworks.com)