Just as Roman letters have a characteristic shape (lower-case letters mostly occupying the x-height, with ascenders or descenders on some letters), Chinese characters occupy a more or less square area in which the components of every character are written to fit in order to maintain a uniform size and shape, especially with small printed characters in Ming and sans-serif styles. Because of this, beginners often practise writing on squared graph paper, and the Chinese sometimes use the term "Square-Block Characters" (方块字 / 方塊字, fāngkuàizì), sometimes translated as tetragraph, in reference to Chinese characters.
What occupy a more or less space area?
Chinese characters