D defs.my
Entry 2 senses Webster, 1913

Springing

· Spring·ing · IPA /ˈspɹɪŋɪŋ/
01 n. The act or process of one who, or that which, springs.
  1. 1.
    The act or process of one who, or that which, springs.
  2. 2.
    Growth; increase; also, that which springs up; a shoot; a plant.
    “Thou blessest the springing thereof.” — Ps. lxv. 10.
Phrases & compounds
Springing line of an 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.