On Wikipedia it says:
Some of the symbols used for chord quality are similar to those used for interval quality:
m, or min for minor, M, maj, or no symbol (see rule 2 below) for major, aug for augmented, dim for diminished.
In addition, however,
Δ is sometimes used for major,[a] instead of the standard M, or maj, − is sometimes used for minor, instead of the standard m or min, +, or aug, is used for augmented (A is not used), o, °, dim, is used for diminished (d is not used), ø, or Ø is used for half diminished, dom is used for dominant.
Is it just tradition or is there a good reason why A and d are not used for augmented and diminished?