The lift curve slope is a measure of how rapidly the wing generates lift with a change in AOA This is Applicable for compressible flow
For a horizontal tail or canard, the pitching moments which must be countered are most directly related to the wing mean chord (Cw). This leads to the "horizontal tail volume coefficient,
If the leading edge and trailing edge are parallel, the chord of the wing is constant along the wing's length. ... The average length of the chord is known as the mean aerodynamic chord (MAC).