"butter shaped into a ball," also figurative of plumpness, 1892, from butter (n.) + ball (n.1).
butler
butt
butte
butt-end
butter
butterball
butter-bean
buttercup
butter-fingered
butterfingers
butterfly
)window.location='https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=byronic106@yahoo.com&lc=US&item_name=Donation+to +Help+Keep+Etymonline+Free+and+Open&no_note=0&cn=&curency_code=USD&bn=PP-DonationsBF:btn_donateCC_LG.gif:NonHosted'){kind=link}