Where does “四畳半” come from?

四畳半 (Japanese) comes from Japanese 四, from Middle Chinese 四, from Proto-Sino-Tibetan *pV-lij — four.

四畳半 (Japanese): a layout of four full-sized and one half-sized tatami for a Japanese-style room

Definitions

  1. a layout of four full-sized and one half-sized tatami for a Japanese-style room

Ancestry of “四畳半”, step by step

四畳半 traces back through 3 separate lines of ancestry.

via Japanese

StepLanguageWordMeaning
1Japanesefour, 4; the fourth
2Middle Chinese
3Proto-Sino-Tibetan*pV-lijfour

via Japanese

StepLanguageWordMeaning
1Japanesetatami; a tatami mat; repeat, duplicate;...
2Japanese畳むfold, especially fold clothes; close down a shop...

via Japanese

StepLanguageWordMeaning
1Japaneseodd; half, semi-; Antonyms
2Middle Chinese
Every word from Proto-Sino-Tibetan *pV-lij