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)
the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions
the way two individuals relate to each other; "their chemistry was wrong from the beginning -- they hated each other"; "a mysterious alchemy brought them together"
an apparatus for burning fuel (or refuse); "a diesel engine is an oil burner"
the heating elements of a stove or range on which pots and pans are placed for cooking; "the electric range had one large burner and three smaller one"