I feel kind of stupid asking this, but what makes an IT an IT?

I'm trying to figure out my current body type, that has morphed from an apple to maybe something else.
I usually think of an Inverted triangle as someone whose hips look narrower from the front than their shoulders. But what if your hip measurement is small but not narrow? My hips don't look much smaller than my shoulders when viewed from the front, but my hip measurement is 4" smaller than my shoulders (totally flat in the back! ) I have very small thighs, too. Does that make me an IT? I don't think of myself as having a particularly strong shoulder line. I have hardly any waist definition, if that matters, so I guess I could be a rectangle.

I suppose it doesn't really matter, but I'm curious.
Any ideas?