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)
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"
the process of ionizing; the formation of ions by separating atoms or molecules or radicals or by adding or subtracting electrons from atoms by strong electric fields in a gas
the condition of being dissociated into ions (as by heat or radiation or chemical reaction or electrical discharge); "the ionization of a gas"
(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.)
sports equipment consisting of an object set up for a marksman or archer to aim at
a reference point to shoot at; "his arrow hit the mark"
the location of the target that is to be hit
intend (something) to move towards a certain goal; "He aimed his fists towards his opponent's face"; "criticism directed at her superior"; "direct your anger towards others, not towards yourself"