Zhong means center, to be in the center, middle, among, medium, halfway. Pronounced as zhòng: to hit the target, to be struck. It is a picture of a pole with a banner, or maybe an arrow, in the middle of a circle.
In the Yi zhong is part of the name of hexagram 61, but in the other hexagrams there are only six places where it occurs. Two of them refer to the sun in the center of heaven: noon.
Center of the forest in hex.3 line 3 is its most simple use.
Three occurences are about 'moving central': 24 line 4 and 42 lines 3 and 4. Moving central can be 'going halfway', 'avoiding any excess', but also 'moving in the center'
Moving in the center is being one with what one does, or following the 'road of the mean', a combination of 'being one with what one does' with 'avoiding any excess'.
China is 'The Middle Kingdom', Zhongguo: the country situated in the center of the earth. Where you are is always the center of the earth: it stretches in all directions around you.
Very interesting is the meaning of 'hitting target' (see Kunst 1985), which expands 'moving central'. You are not only staying in between two extremes, but 'hitting target' while doing it.
Zhong on Oracle Bones