Futon came into English in 1876 straight from Japanese, and it shows the shape that marks Japanese borrowings: simple consonant-vowel syllables, no clusters, nothing English has to wrestle with. Tsunami, sushi, karaoke, tycoon and futon all share that easy structure, which is why they arrive in English almost unaltered — there is nothing in them for English to mangle.
That makes the Japanese layer unusual. Most borrowings get reshaped on the way in: Nahuatl loses its tl, Arabic keeps a fused article it never meant to give away, Spanish loses its tilde. Japanese words mostly just walk in. The Japanese word is said to mean a bedroll or a place to rest, and the English sense has drifted only in the way the object has — from a rolled mattress to a piece of convertible furniture.
futon (n.) 1876, from Japanese, said to mean "bedroll" or "place to rest." also from 1876
futon came in through Later and wider borrowings, and its spelling follows that family's conventions.
How that family writes these sounds
| no consonant clusters, every syllable open | Japanese: write it exactly as it soundstsunami, sushi, karaoke, futon |
What gives it away on the page
| no consonant clusters, every syllable open | Japanese.tsunami, sushi, karaoke, futon, tycoon |
Later and wider borrowings in the spelling guide · guess another word's family