So what's a nomad?

When I learned the word, nomads were hunters or herdsmen with no fixed abode.  They followed the game or the graising, striking their tents and moving on as the food sources moved them.  Like Abraham. 
   So I am reading "Stonehenge, the Indo European heritage", by Leon Stover and Bruce Kraig, some European archeaology, discussing the earliest European site.  And this amazing phrase pops up.  "a nomadic people who farmed,clearing forest land for dispersed settlements as they passed." 
   Oh really.  Once they put in the hard work to clear the land and plant, they aren't going to strike their tents and move on, not until the harvest is in anyhow.  And probably not after harvest either.  Harvest ought to produce enough food to get thru the winter, which is entirely too heavy to take with them.  It's generally accepted that farming makes the settled life possible.  The transition from hunter and herder to farmer is the end of the nomadic life.  So, "a nomad people who farmed" makes one wonder about the author's common sense.
   He is describing the "Danubian" or "Linear Pottery" folk, who settled western Europe before the coming of the Indo Europeans.  But he doesn't offer any evidence (potsherds, flints, gravegoods, etc) that the Danubians were nomadic.  So he throws out a hard to swallow concept with no backup.