What is "spear side"

Spear \Spear\, n. [OE. spere, AS. spere; akin to D. & G. speer, OS. & OHS. sper, Icel. spj["o]r, pl., Dan. sp[ae]r, L. sparus.]

1. A long, pointed weapon, used in war and hunting, by thrusting or throwing; a weapon with a long shaft and a sharp head or blade; a lance.

   Note: [See Illust. of Spearhead.] ``A sharp ground spear.''
   --Chaucer.

   They shall beat their swords into plowshares, and their spears into pruning hooks.
   --Micah iv. 3.

2. Fig.: A spearman.
   --Sir W. Scott.

3. A sharp-pointed instrument with barbs, used for stabbing fish and other animals.

4. A shoot, as of grass; a spire.

5. The feather of a horse. See Feather, n., 4.

6. The rod to which the bucket, or plunger, of a pump is attached; a pump rod. Spear foot, the off hind foot of a horse. Spear grass. (Bot.)

   1. The common reed. See Reed, n., 1.

   2. meadow grass. See under Meadow.

      Spear hand, the hand in which a horseman holds a spear; the right hand.
      --Crabb.

      Spear side, the male line of a family.
      --Lowell.

      Spear thistle (Bot.), the common thistle ( Cnicus lanceolatus).