a bit; a trifle; a tiny amount
Rare literary noun for a very small quantity or degree. Often used in negative contexts to mean 'not even a bit'. Modern equivalents include 少し, わずか, or ほんの少し.
There was not a grain of truth in his words.
Without a shadow of a doubt, he thought he was right.
tiny amount; the slightest bit
Compound of 一 (one) and 毫 (fine hair, minute amount). The character 毫 originally referred to a fine brush hair, metaphorically a very small unit. The exact historical derivation is uncertain, but the word is a classical Chinese borrowing.