What does "springing" mean?

Springing: Growth; increase; also, that which springs up; a shoot; a plant. Thou blessest the springing thereof. Ps. lxv.

Additional senses

  1. 2.Springing line of an arch (Arch.), the horizontal line drawn through the junction of the vertical face of the impost with the curve of the intrados; -- called also spring of an arch.

Sources