The above symbol is the GuaXiang(Image) of the 24th Gua in the Book of Changes, or Yi Jing. Its chinese character is ¸´, meaning the "yang" starts increasing right after all "yin" Kun(the Earth). It also represents about five or six days after winter solstice, meaning that it is time for everything to revive, which is also the meaning of the chinese character ¸´.
Yiyang/Ò»Ñô just means the last row of this symbol, stands for the very first "yang" appear in the world after all "yin" rules. This row is the essential part of the whole symbol.