a very small piece
smallest possible amount
any of a number of usually short words that are not as important in a sentence as the subject, verb, etc.
The fat droplets have been broken up into much smaller particles.
出自： B. Spock
Mud..formed from the still finer particles of material carried out from the coast.
出自： A. Hardy
In the shafts of light..she could see particles moving.
出自： E. Figes