the part of a bow grasped when shooting
弝 refers specifically to the grip of a bow, the part held when shooting. It is a narrow technical term without broader abstract extensions.
弝 combines 弓 (bow) with 巴, which likely contributes a phonetic element. The character specifically denotes the grip part of a bow.
The bow radical 弓 on the left is paired with 巴, which looks like a hand gripping something. Picture a hand wrapped around the curved grip of a bow: that is 弝.
For ハ, imagine the sound of a sharp 'ha!' as you grip the bow tightly before releasing the arrow: 'ha!' -> ハ.