a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust
a common nonmetallic element that is normally a colorless odorless tasteless inert diatomic gas; constitutes 78 percent of the atmosphere by volume; a constituent of all living tissues
a heavy odorless colorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis
the act of distinguishing by comparing differences
the range of optical density and tone on a photographic negative or print (or the extent to which adjacent areas on a television screen differ in brightness)
the perceptual effect of the juxtaposition of very different colors
the opposition or dissimilarity of things that are compared; "in contrast to", "by contrast"
put in opposition to show or emphasize differences; "The middle school teacher contrasted her best student's work with that of her weakest student"
to show differences when compared; be different; "the students contrast considerably in their artistic abilities"
a volatile flammable mixture of hydrocarbons (hexane and heptane and octane etc.) derived from petroleum; used mainly as a fuel in internal-combustion engines