|Ron Cobb's 1969 Ecology Symbol|
The Earth Day name
According to Nelson, the moniker "Earth Day" was "an obvious and logical name" suggested by "a number of people" in the fall of 1969, including, he writes, both "a friend of mine who had been in the field of public relations" and "a New York advertising executive," Julian Koenig. Koenig, who had been on Nelson's organizing committee in 1969, has said that the idea came to him by the coincidence of his birthday with the day selected, April 22; "Earth Day" rhyming with "birthday," the connection seemed natural so the name stuck.
Please read further on Wikipedia: "Earth Day" HERE