pentahedron/pentəʹheedrən, -ʹhedrən/ noun (pl pentahedrons pentahedra /-drə/)

• oxygen mask
• oxygen tent
• oxyhaemoglobin
• oxymoron
• oxytetracycline
• oxytocin
• oyer and terminer
• oyez
• oyster
• oyster bed
• oystercatcher
• oyster mushroom
• oyster plant
• Oz
• oz.
• Ozalid
• ozocerite
• ozone
• ozone-friendly
• ozone layer
• ozonize
• ozonosphere
• o’
• P
• p