I'm having a bit of a fight with Digi-Key over the description on their website, which describes the part as "IC REG LDO ADJ 1.5A SOT223", LDO being the problematic bit. Throughout industry and TI's own documentation, LDO is defined as "low dropout":
http://www.ti.com/lit/ml/slup239/slup239.pdf
http://www.ti.com/lit/an/sbva026e/sbva026e.pdf
http://www.ti.com/lit/sg/slyt228l/slyt228l.pdf
https://en.wikipedia.org/Low-dropout_regulator
Yet, Digi-Key is stuck on the fact that, for some unfortunate reason, the LM317 product page at TI places it and many others in the category "Linear Regulator (LDO) > Single Channel LDO". Thus they are erroneously adding LDO to the description.
It looks to my like all linear regulators on the TI site are put into this "Linear Regulator (LDO)" category, whether the LDO tag applies to them or not. As stated by one TI employee, https://e2e.ti.com/support/power_management/linear_regulators/f/321/t/248252, the LM317 is not an LDO.
It's sort of like a typo, but some poor sap that rushes into using the LM317 thinking that he has an LDO without properly interpreting the specification could get bitten, don't you think?