copepod, copepod crustacean - minute marine or freshwater crustaceans usually having six pairs of limbs on the thorax; some abundant in plankton and others parasitic on fish mussel shrimp, ostracod, seed shrimp - tiny marine and freshwater crustaceans with a shrimp-like body enclosed in a bivalve shell
time and a half(noun) a rate of pay that is 1.5 times the regular rate; for overtime work.
But it is possible to measure how long it takes for half the nuclei of a piece of radioactive material to decay. This is called the half-life of the radioactive isotope. There are two definitions of half-life, but they mean essentially the same thing. Half-life is the time taken for: 1  The number of nuclei of the radioactive isotope in a sample to halve. 2  The count rate from a sample containing the radioactive isotope to fall to half its starting level.