In both Japanese and Chinese script: = "way"
Pinyin: Dào Wade-Giles: Tao Jap: Dò

Composition of the Chinese Tao as in Taoism.
(Source: Wenlin)

According to Rose Quong in her book Chinese Written Characters: Their Wit and Wisdom, the Tao character is decomposed to mean "the path of the warrior," where warrior-monks were the original keepers of both martial arts and spiritual knowledge and wisdom.
The decomposition etymology for the character is distinguished by the tufts at the top, representing the distinctive hairstyle of the warrior class (a "bun"). The character itself is used to refer to concepts related to the head, such as leadership and rulership.

This is meant to be evocative of its meaning "to walk," and "to go," as well as the generic radix for "the way of."