Kanji radicals

Because there are so many kanji, they are grouped by radicals and by number of strokes.
Radicals are simple kanji that are contained in more complex kanji. Radicals are also kanji.

艸 is radical for grass. Kanji for flower 花 and tea 茶 both contain the radical for grass.
Kanji for ice 氷contains kanji for water 水.