phaen- /fēn-/ or phaeno- /fē-no- or -nō-/ same as phen- or pheno-

• OPEC
• op-ed
• opeidoscope
• opeidoscopes
• open
• openable
• open access
• open-access
• open adoption
• open aestivation
• open-air
• open-and-shut
• open a person's eyes
• open-armed
• open book
• plaiter
• plaiters
• plaiting
• plaitings
• plaits
• plan
• planar
• planar diode
• planar diodes
• planarian