Barb
A horizontal branch from the shaft (RACHIS) of a feather, also called a 'ramus'. It carries the 'barbules' which are so arranged that those on one barb interlock with those of its neighbours, being held by tiny hooks called 'barbicels' or 'hamuli'. With this arrangement a bird has only to run its bill along a disarrayed feather while preening to return it to its proper neatness. The barbs taken all together make up the 'vane' or 'web' of the feather.From Peter Weaver's Birdwatcher's Dictionary
Copyright © 1981 by Peter Weaver