1. On a railway flatcar
   - piggyback, pig-a-back 
2. On the back or shoulder or astraddle on the hip
   - piggyback, pig-a-back

Encyclopedia: Pickaback

• 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
• photocathode
• photocell