at·om 
/ˈætəm/ noun
plural at·oms /ˈætəm/ noun [count] 1 : the smallest particle of a substance that can exist by itself or be combined with other atoms to form a molecule
▪ carbon atoms ▪ an atom of hydrogen 2 : a very small amount of something
▪ The flu took every atom [=bit] of strength I had. ▪ There is not an atom of truth to what he said.
▪ carbon atoms ▪ an atom of hydrogen
▪ The flu took every atom [=bit] of strength I had. ▪ There is not an atom of truth to what he said.
