"quatrains" (in Persian poetry), 1859, plural of rubai, from Arabic rubaiyah, from rubaiy "composed of four elements."
rpg
rpm
rRNA
rub
rub-a-dub
rubaiyat
rubato
rubber
rubberneck
rubbers
rubbery
)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}