續一切經音義 1.171

1.171

拇指（上莫譜反韻英云拇謂手足大指說文云從手母聲母字從女中二點像母兩乳形有作母音無止之辞母母全別）。

Thumb / big toe (拇指) (The first [character] has the fanqie mò + pǔ [mǔ]. The Yunying states: 'Mǔ refers to the great digit of the hand or foot.' The Shuowen states: 'It derives from hand (手) with the phonetic mǔ (母).' The character mǔ (母) derives from woman (女), with two dots in the middle resembling the shape of a mother's two breasts. Some write it as 毋, which has the sound wú, meaning a particle of prohibition; 母 and 毋 are completely different).