a streak of light in the sky at night that results when a meteoroid hits the earth's atmosphere and air friction causes the meteoroid to melt or vaporize or explode
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)
(theology) the origination of the Holy Spirit at Pentecost; "the emanation of the Holy Spirit"; "the rising of the Holy Ghost"; "the doctrine of the procession of the Holy Spirit from the Father and the Son"
something that is emitted or radiated (as a gas or an odor or a light etc.)
cartilaginous fishes having horizontally flattened bodies and enlarged winglike pectoral fins with gills on the underside; most swim by moving the pectoral fins
any of the stiff bony rods in the fin of a fish
a branch of an umbel or an umbelliform inflorescence
(mathematics) a straight line extending from a point
emit as rays; "That tower rays a laser beam for miles across the sky"
syndrome resulting from exposure to ionizing radiation (e.g., exposure to radioactive chemicals or to nuclear explosions); low doses cause diarrhea and nausea and vomiting and sometimes loss of hair; greater exposure can cause sterility and cataracts and some forms of cancer and other diseases; severe exposure can cause death within hours; "he was suffering from radiation"
a toxic condition caused by ingesting or inhaling mercury; acute mercury poisoning causes a metallic taste and vomiting and diarrhea and kidney problems that may lead to death