Fitted tops are a tighter fit. Non-fitted tops are a looser fit.
Why gender-neutral labels? At Shelter we want to allow you to be your authentic self, however you self-identify. Labelling clothes neutrally is one way we're trying to make our shopping experience inclusive to all.
The labels in the tops themselves do not currently use gender-neutral language. Fitted tops will come labelled as women's and non-fitted tops will come labelled as men's.