in, inside, middle, mean, center
中 centers on the idea of being inside a bounded space or interval: in, inside, middle, or center. The sense of 'mean' (as in average) extends naturally from the middle point of a range.
(all) through (e.g. the night); throughout (e.g. the year); all ... long
medium (size); average (grade, level, etc.); middle
inside; interior
China
very; considerably; easily; readily; fairly; quite; highly; rather
center; centre; middle; heart; core; focus; pivot; emphasis; balance
on the way; en route
centre; center; middle; heart
concentration (on a task); focusing one's attention
company; lot; people; bunch; gang; pack; guys; group; folks
contents; interior; filling
interruption; discontinuance; suspension; stoppage
society; the world; the times
around the world; throughout the world
back (of the body)
junior high school; middle school; lower secondary school
junior high school student; middle school pupil
relay; hook-up
used; second-hand; old
middle; centre; center; midpoint; heart
China
middle; midway; halfway; centre; center
Middle Ages (in Japan esp. the Kamakura and Muromachi periods); medieval times; mediaeval times
junior high school; middle school; lower secondary school
中 is a pictograph of a line or flagpole piercing the center of a box or target, representing the middle or inside.
The vertical line ｜ passes straight through the center of the box 口, marking the exact middle. Picture an arrow hitting the bullseye: 中 is the center, inside the target.
For チュウ, imagine a cheerful 'chew' sound as you bite into the center of a juicy fruit: chew -> チュウ, and the sweet middle is the best part.