In anatomy, the thumb is called the first digit.
Common everyday word for 'thumb'. 拇指 is a formal anatomical term used mainly in medical contexts.
Refers to the big toe, not the thumb. Same reading but different kanji (趾 vs 指).
opposable thumb; thumb opposition
Standard kanji spelling for the anatomical term 'thumb'.
Alternate spelling; 母 (mother) is used phonetically. Less common than 拇指.
Irregular kanji usage; 栂 is a non-standard character for this word. Not recommended for learners.
From Chinese 拇指 (mǔzhǐ), combining 拇 ('thumb') and 指 ('finger'). The reading ぼし is the on'yomi of the characters.