1. Toward the source or against the current
   - upstream

Antonym: downriver

• phosphoresce
• phosphorescence
• phosphorescent
• phosphoric
• phosphoric acid
• phosphorite
• phosphorous
• phosphorous acid
• phosphorus
• phosphoryl
• phot
• photalgia
• photic
• Photinia
• Photinia arbutifolia
• Photius
• photo
• photo credit
• photo finish
• photo op
• photo opportunity
• photo-offset
• photo-offset printing
• Photoblepharon
• Photoblepharon palpebratus