Is a shoulder or a sidelobe?

Hi, Does anyone know the distinction between "shoulder" and "side lobe" of an antenna pattern? Can I consider a 2.5db deep sidelobe as a shoulder?
Tanks in advance.

I think the "shoulder" is a expert slang expression for a main lobe which is not looking like a single clean loop; if it has as you say ~ 2.5 dB widening, such effect can be named a "shoulder". Real side lobes are usually >10 dB smaller than the main lobe peak, and between the main lobe and a side lobe there usually is a deep notch, typically 20 dB or more down from the main lobe.