Particles (5)
'particles' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for iotas that I've seen before include "Tiny amounts" , "Jots, very small amounts" , "Tiny scraps" .)
'particles' is the definition.
('atom' can be a synonym of 'particle')
This is the entire clue.
(Other definitions for atoms that I've seen before include "Jots" , "Dots" , "Minute particles" , "small fragments" , "Small particles" .)