No, really, I have MSc in physics but I have no idea what a thing being 'a feature' specifically means in the cosmological sense - quick googling also fails to

No, really, I have MSc in physics but I have no idea what a thing being 'a feature' specifically means in the cosmological sense - quick googling also fails to find specification for the term. If it's significant then it is significant within a specific model and elements of said model should be able to be specified with logical precision - otherwise the said model is kinda pointless. Clearly what they are seeing is a large scale anisotropy - so what's the treshold for an anisotropy to be considered to be 'a single structure' and how is it measured?