Lambda

The creator of the symbol is graphic designer Tom Doerr.

Lambda was first selected in as a symbol of gays, when she was adopted in 1970 by the New York City Gay Activists Alliance. She has become a symbol of the growing gay liberation movement. In 1974, the lambda was adopted by the International Congress for Gay Rights in Edinburgh, Scotland. As a symbol of lesbian and gay rights, lambda has become popular all over the world.

No one can say for sure why this letter became a symbol of the gay and lesbian movement.

Some suggested use lambda in physics to denote energy or wavelength ... The ancient Greek Spartans considered lambda to be a unity, and the Romans considered it: "the light of knowledge penetrated the darkness of ignorance." The ancient Greeks reportedly placed lambda on the shields of Spartan warriors, who often paired up with young men in battle. (There was a theory that warriors would fight more sharply, knowing that their loved ones were watching and fighting alongside them.) Today, this symbol usually denotes lesbian and gay men.