The Meadow is an area on the east side of the world map. You can explore the Meadow if you have a Homegrown Carrot (bought from Farmed Foods during the Season of Leaves or found by digging at the Meadow Farm).
Areas of Interest:
Rivvid Tunnel
The rivvid tunnel is a special area at the top-left corner of the Meadow. Looks like you need to get past him to get in.
More info on Rivvid tunnel
More info on Rivvid tunnel