iota
Itty
Iota.
The 4-letter word that means a small amount of something is "mite." A mite is a very small amount or portion of something, often used to indicate a tiny quantity. It can also refer to a tiny arachnid belonging to the Acari order.
small
Tiny
tiny
It means that the thing referred to is so tiny that it is immeasurably tiny.
Akin , like ,
a small or tiny part, amount, or proportion of something
Chip
Cilia.
Tuui