1. (informal) assist and protect 
2. (informal) ride in the front passenger seat of a vehicle, next to the driver

Encyclopedia: Ride shotgun

• plow ahead
• plow horse
• plowboy
• plowed
• plower
• plowing
• plowland
• plowman
• plowshare
• plowwright
• ploy
• pluck
• pluck at
• plucked
• pluckily
• pluckiness
• pluckless
• plucky
• plug
• plug away
• plug fuse
• plug hat
• plug in
• plug into
• plug-ugly