''loss ''' may refer to:

• A negative difference between retail price and cost of production
• An event in which the team or individual in question did not win.
• Loss (baseball), a pitching statistic in baseball
• Attenuation, a reduction in amplitude and intensity of a signal
• In telecommunications, loss is a decrease in signal in a communications system:
• Angular misalignment loss, power loss caused by the deviation from optimum angular alignment
• Bridging loss, the loss that results when an impedance is connected across a transmission line
• Coupling loss, the loss that occurs when energy is transferred from one circuit, optical device, or medium to another
• Insertion loss, the decrease in transmitted signal power resulting from the insertion of a device in a transmission line or optical fiber
• Path loss, the attenuation undergone by an electromagnetic wave in transit from a transmitter to a receiver
• Free-space path loss, the loss in signal strength that would result if all influences were sufficiently removed having no effect on its propagation
• Reflection loss, a loss which causes energy to be reflected back toward its source
• Return loss, the ratio of the amplitude of the reflected wave to the amplitude of the incident wave
• in laser physics, loss (or background loss, or round-trip loss) may refer to the part of the energy of the optical field, that becomes unusable at each rond-trip in the cavity due to the scattering or absorption.

In the arts:

• Loss (film), a 2008 film by Maris Martinsons.
• Joe Loss, the founder of The Joe Loss Orchestra
• Loss (album), the debut album of Mull Historical Society
• Loss (comics), a mutant comic book character
• Lord Loss (character), the Demon Lord from Darren Shan's 10 book series The Demonata
• "The Loss" (TNG episode), a fourth-season episode of Star Trek: The Next Generation