əˈtɔmɪk adj. 1
concerned with or using atomic
energy or atomic bombs. 2 of or relating to an
atom or atoms. øatomic
bomb = atom bomb. atomic clock a clock in
which the periodic process (time scale) is regulated by the vibrations of an atomic or
molecular system,
such as
caesium or
ammonia. atomic energy
nuclear energy. atomic mass the mass of an atom
measured in atomic mass units. atomic mass
unit a unit of mass used to express atomic
and molecular weights
that is
equal to
one twelfth of the mass of an atom of carbon-12. °Abbr.:
amu. atomic
number the number of protons in the
nucleus of an atom, which is
characteristic of a
chemical element and determines
its place in the periodic
table. °Symb.: Z. atomic
particle any one of the particles of which an atom is constituted. atomic
philosophy atomism. atomic
physics the
branch of physics concerned with the
structure of the atom and the characteristics of the
elementary particles of which it is composed. atomic pile a nuclear
reactor. atomic
power nuclear power. atomic
spectrum the
emission or
absorption spectrum arising
from electron transitions
inside an atom and characteristic of the element. atomic structure the structure of an atom as
being a
central positively charged nucleus surrounded by negatively charged orbiting electrons. atomic
theory 1 the
concept of an atom as being composed of elementary particles. 2 the theory that
all matter is
made up of
small indivisible particles called atoms, and that the atoms of any one element are
identical in all respects but
differ from
those of
other elements and
only unite to
form compounds in fixed proportions. 3 Philos. atomism. atomic
warfare warfare involving the
use of atom bombs. atomic
weight =
relative atomic mass. øøatomically adv. [mod.L atomicus (as ATOM, -IC)]