Chinese radical

A radical is a component of a Chinese character under which the character is often listed in a dictionary. A radical often indicates what the character means.

For instance characters which contain the grass radical are related to plants. The grass radical has two forms: 艸 and 艹. The latter is being used when the radical is at the top of a Chinese character.

Some examples containing 艹 at the top:

草 (cao3) = grass
芋 (yu4) = taro
花 (hua1) = flower, blossom
茶 (cha2) = tea
菜 (cai4) = vegetables
葉 (ye4) = leaf
薑 (jiang1) = ginger
藥 (yao4) = (herbal) medicine

In Chinese a radical is called 部首 (bùshǒu). 部 (bù) means "section" while 首 (shǒu) means "head" or "header", so a radical is basically a section header. The reason being that words are organised according to radicals in many dictionaries.