it means exesive pigmentation (color), as of the skin
The hot water supply valve you turned off to allow you to cut into the hot water pipe is still turned off. This valve was probably an old gat typr valve that failed in the closed position and although the handle moved the mechanism insid did not. This is a common failure with that type of valve.
The yellowcake is the ammonim diuranate with the formula (NH4)2U2O7 !
Flews are the large overhanging sides of the upper lips of some (usually large) dogs, such as Great Danes, Saint Bernards, etc. Or...could you have possibly meant "flue," as in a chimney pipe, organ tube, or fishing net?
Convection is heat transfer by movement hot matter as compared to cold matter bure to density differences in the presence of a gravity field.
heat transfer through moving currents