Juliet's mark

From Lostpedia

Juliet's mark

As part of his commuting Juliet's death sentence in "Stranger in a Strange Land", Ben orders Juliet to be marked instead. Jack asks Juliet to show him the mark and she reveals a strange symbol branded onto her lower back. The symbol looks somewhat like an upside-down cross (with the top line longer than the others), with two (or four) lines facing away from the center on the horizontal line. The mark is raised, reddened, and inflamed. Jack then treats it with an aloe leaf.

It is similar to the symbols for the Hand of Eris, Pisces, ammonium salt (in alchemy), and the Red Hot Chili Peppers' symbol. It is also similar to an upside-down Christian cross with rays of Light coming from intersection.

Trivia

Juliet is given her mark in "Stranger in a Strange Land", the same episode in which the origin of Jack's own tattoo (which also has stars) is revealed.
In the Bible, the mark of Cain is God's symbol of both shame over Cain's actions, and a commandment that he not be killed.
Juliet's mark has certain visual similarities to the tree mark but there is no evidence yet to conclude that they are the same symbol or what either symbol means.
In the March 30th, 2007 Podcast, Elizabeth Mitchell alludes to the mark meaning Juliet is a traitor and a killer.
Juliet's mark is believed by some fans to be an Easter egg in reference to Easter eggs; the same symbol is found on Cadbury creme eggs, which are associated with Easter.
Juliet's mark also resembles an inverted version of the 8-armed cross that symbolizes the Church of Scientology.