Prefix that intensifies a location or state, meaning 'right in the middle', 'dead center', 'perfectly round', etc. Used in a limited set of compounds; not freely productive.
Please stand right in the middle.
A perfectly round moon was in the sky.
perfectly round; perfect circle · adorably round; cute
right in front; just opposite; under one's nose
right in the center; dead center; exact middle
perfectly round; perfectly circular
dead center; right in the middle
Derived from the prefix 真 (ま) with an inserted ん, possibly for euphony or emphasis. The exact historical development is uncertain.