Eccentrically loopy ... like this (8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

We had to check this. We both knew what an ellipse was from our A Level Maths days but thought that ‘eccentrically loopy’ was a rather strange definition. However, on checking in Chambers, an ellipse can also refer to the mark … – so perhaps we have a double definition here.