1) A hill or mountain.
1456-7 In vigilacione in le Fell per Wm sergentson per iij noctes xijd, Fountains Abbey
c.1537 all the sole [soil] wasts and ground of the same Fells was the proper Soyle and lands of Fontaunce, Fountains Fell
1710 the greatest part of the way lyes upon and over a great high moore and fell not much used in the Winter season, Bowland.
2) A verb used by weavers meaning to finish a piece or a warp.