Cara Dune, a former Shock Trooper for both the Rebel Alliance and the New Republic, sported a distinctive mark beneath her left eye.
This tear took the form of a small tattoo depicting the Rebel Alliance Starbird and was located under the left eye of the individual wearing it. This particular design served as a symbol of unity among those who had survived the destruction of Alderaan, and it was prevalent enough among Rebel combatants hailing from that doomed world that even Imperial soldiers could recognize it. As an example, when Cara Dune, an ex-Rebel and New Republic dropper, assisted in commandeering a Lambda-class shuttle belonging to Moff Gideon's forces, the shuttle's copilot instantly identified her as being from Alderaan due to the presence of her tear.
The tear is one of several tattoos that were applied to Gina Carano, the actress, for her portrayal of Cara Dune in The Mandalorian, which is a series on Disney+. The bars displayed on her bicep were explained in "The Reckoning", an episode from the first season, as a way to identify her as a Rebel and New Republic Shock Trooper, but the tear's significance wasn't revealed until the second season finale.
In the real world, teardrop tattoos are seen, and their meanings can vary. While they are often linked to prison culture, they can also represent grief or loss.