the time required for something to fall to half its initial value (in particular, the time for half the atoms in a radioactive substance to disintegrate)
a rocket-propelled guided missile that can escape the earth's atmosphere; makes observations of the solar system that cannot be made by terrestrial observation
a compound made artificially by chemical reactions
of a proposition whose truth value is determined by observation or facts; "`all men are arrogant' is a synthetic proposition"
systematic combining of root and modifying elements into single words
involving or of the nature of synthesis (combining separate elements to form a coherent whole) as opposed to analysis; "limnology is essentially a synthetic science composed of elements...that extend well beyond the limits of biology"- P.S.Welch
not genuine or natural; "counterfeit rhetoric that flourishes when passions are synthetic"- George Will
excessively and uncomfortably conscious of your appearance or behavior; "self-conscious teenagers"; "wondered if she could ever be untidy without feeling self-conscious about it"
aware of yourself as an individual or of your own being and actions and thoughts; "self-conscious awareness"; "self-conscious about their roles as guardians of the social values"- D.M.Potter
the metabolic processes whereby certain organisms obtain energy from organic molecules; processes that take place in the cells and tissues during which energy is released and carbon dioxide is produced and absorbed by the blood to be transported to the lungs
a single complete act of breathing in and out; "thirty respirations per minute"
respirator that produces alternations in air pressure in a chamber surrounding a patient's chest to force air into and out of the lungs thus providing artificial respiration