What these TBLG symbols mean…
The pink triangle originated from the Nazi concentration camp badges that
homosexuals were required to wear on their clothing. the pink triangle is used both
as an identification symbol and as a memento to remind both its wearers and the
general public of the atrocities that gays suffered under Nazi persecutors.
ACT-UP (AIDS Coalition to Unleash Power) also adopted the inverted pink triangle to
symbolize the “active fight back” against the disease “rather than a passive resignation to fate.”
Lambda
In 1970, the Greek letter lambda (λ) was selected to symbolize the Gay Activists
Alliance’s campaign for gay liberation, and, four years later, the International Gay
Rights Congress in Edinburgh, Scotland, chose the same symbol to represent
lesbian and gay rights. As a result, the lambda has become internationally known.
It is traditional for the lambda to be shown in lavender, a color which, like pink, is
often associated with homosexuality. The lambda, in physics represents energy,
and therefore is used to symbolize the energy of the Gay Rights Movement.
Rainbow flag, Current version of the Gay pride flag
The rainbow flag was designed for the 1978 San Francisco's Gay Freedom
Celebration. The colors of the rainbow are displayed as horizontal stripes,
with red at the top and purple at the bottom. It represents the diversity of
gays and lesbians around the world. Red stands for life, orange stands for
healing, yellow stands for sun, green stands for nature, blue stands for harmony, and purple
stands for soul.
Bisexual Double Triangle or Overlapping Triangle symbol
represents bisexuality and bi pride. The exact origin of this symbol
remains ambiguous. It is popularly thought that the pink triangle may
represent homosexuality, as it does when it stands alone, while the blue
stands for heterosexuality. The two together form the color lavender, a blend of
both sexual orientations and a color that has been associated with homosexuality
for almost a century.
Transgendered symbol used to identify transsexuals, and other transgender
people, frequently consists of a modified biological symbol. In addition to the
arrow projecting from the top right of the circle that comprises the biological
symbol for the male, and in addition to the cross projecting from the bottom of the
circle that comprises the biological symbol for the female, the symbol incorporates both
these devices as well as a cross topped by an arrowhead (combining the male and the
female motifs).
From: http://en.wikipedia.org/wiki/LGBT_symbols