a part of the cell containing DNA and RNA and responsible for growth and reproduction
any histologically identifiable mass of neural cell bodies in the brain or spinal cord
the positively charged dense center of an atom
(astronomy) the center of the head of a comet; consists of small solid particles of ice and frozen gas that vaporizes on approaching the sun to form the coma and tail
the quality imparted to voiced speech sounds by the action of the resonating chambers of the throat and mouth and nasal cavities
a vibration of large amplitude produced by a relatively small vibration near the same frequency of vibration as the natural frequency of the resonating system
an excited state of a stable particle causing a sharp maximum in the probability of absorption of electromagnetic radiation
the branch of quantum physics that accounts for matter at the atomic level; an extension of statistical mechanics based on quantum theory (especially the Pauli exclusion principle)
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 number of observations in a given statistical category
the ratio of the number of observations in a statistical category to the total number of observations
the number of occurrences within a given time period; "the frequency of modulation was 40 cycles per second"; "the frequency of his seizures increased as he grew older"
a wave resulting from the periodic flow of the tides that is caused by the gravitational attraction of the moon and sun
an unusual (and often destructive) rise of water along the seashore caused by a storm or a combination of wind and high tide
an overwhelming manifestation of some emotion or phenomenon; "a tidal wave of nausea"; "the flood of letters hit him with the force of a tidal wave"; "a tidal wave of crime"
(music) the distinctive property of a complex sound (a voice or noise or musical sound); "the timbre of her soprano was rich and lovely"; "the muffled tones of the broken bell summoned them to meet"
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)