Riyadh UK /ˈriː.æd/US /ɹiˈjɑːd/ noun2 •The capital city of Saudi Arabia.U.S. President Donald Trump delighted his Saudi hosts in Riyadh on May 13, telling them America wouldn’t be giving “lectures on how to live” under his watch. — 2025 •A province of Saudi Arabia. Capital: Riyadh.