The shell bone script of character Main is
The bottom of all three above is Wood (tree), the top is ancient Chinese mortise and tenon structure, similar to the joint structures below
Ancient Chinese didn't use any nails to build house because they invented the mortise and tenon technique.
The middle top is the mortise and tenon joint, which is the most important structure for the house: The main pillar.
The big seal script of the character is
The top is similar to shell bone script, but the bottom is character Soil, not Wood. Some people believe that the top still a mortise and tenon joint, but others think that the top is a flame keeper, which was not easy to keep in the ancient time, very important thing to people.
The small seal script of the character is
Similar to big seal script, but the top middle is more like flame.
The clerical script of the character is
Same as to clerical script.
Its Pinyin is Zhu3.
主 also means Host, Owner, Lord, etc.