The tattoo is likely a reference to her past struggles drug addiction and eating disorders, something that Demi has been open about in the past.
Talking at Teen Vogue Summit earlier this year, Demi spoke about being a 'fighter' and is committed to being the best person she can be.
"What I see in the mirror [is] someone that’s overcome a lot. I’ve been through a lot and I genuinely see a fighter.
"I don’t see a championship winner, but I see a fighter and someone who is going to continue to fight no matter what is thrown their way."
The last tattoo Demi got was a simple 'T', a tribute to her close friend Thomas Trussell III who passed away from a drug overdose in October.
"A T for Tommy. RIP you special angel. Love you forever @sirtruss,” Demi wrote at the time. “If you or someone you know is struggling with addiction, please do not hesitate to ask for help. Please call 877.921.9653."