真ん円い
まんまるい · manmarui · JLPT N1 · noun
round
🌕 真 = true/perfect + 円 = circle + い: a true circle, so perfectly round
The 真 prefix intensifies its word, like 'true' in 'true north'. The ん between 真 and 円 is a sound linker, so the word is said manmaru, with a round, rolling sound.
真 — 匕 (spoon) over 目 (eye) over 八 (eight/base)
真 originally depicted a person or vessel used in ritual, conveying the idea of something genuine or true. Over time the form was reanalyzed as components like 匕, 目, and a base, but the core meaning of 'real, true, genuine' has remained stable since early bronze inscriptions.