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

• Mexicano
• Mexico
• Mexico City
• mexiletine
• Mexitil
• Meyer Guggenheim
• Meyerbeer
• Meyerhof
• mezcal
• mezereon
• mezereum
• mezuza
• mezuzah
• mezzanine
• mezzanine floor
• mezzo
• mezzo-relievo
• mezzo-rilievo
• mezzo-soprano
• mezzotint
• MF
• MFA
• MFLOP
• mg
• mho