1) An unploughed piece of land in the open field, used as a field division and also a right of way.
1558 two halfe acars of the midle dayleflat next the balke, Monk Fryston
1610 ploweth one furrow through of my grene balkes, Brandsby
1679 did plowe upp an ancient balke in Netherfeild, Mirfield
1711 hath left out a balke for a footpath of the outside of the hedge, being as convenient for any neighbours to go that way, Scholes. The word is on record from the Old English period and is an element in many early place-names.
2) Where wood is concerned, the balk is a strong, roughly squared piece of timber, a beam.
1433 ij quercubus squararatis pro balkes, York
1612-3 all baulk trees about the house and barne, Harrogate
1686 Two Balkes … to be delivered A foot Square through out & 19 foot in length, Conistone. It was used particularly of the tie-beams which stretched from wall to wall: 1696 upon the maine Bawke of the house, Leeds. These were used for hanging articles on, especially meat: 1559 Item flesh hanging of balkes, North Stainley
1618 Item beiff at baulks, Cottingley. When planks or boards were laid across the beams the space above came to be called ‘the balks’: 1549 fleche hengyng in the bawkes, Marrick
1647 one stampe of hay lying in the balkes in the lowe barne, Hampsthwaite
1783 finisht our hay which was on the Balks, Ovenden. Occasionally the reference was to a horizontal iron bar in the chimney: 1433 unum instrumentum ferreum in camino aulć, vocatum balk, York
1486 the yren balk in the chymnay, Hull.
3) Of cloth, in the raw or unfinished state (OED).
1758 cloath betwixt 2s and 2s 6d per yard in bauk is called middles, Wakefield.