%subject-matter%

n. The matter or thought presented for consideration in some statement or discussion; that which is made the object of thought or study. [ 1913 Webster ]

As to the subject-matter, words are always to be understood as having a regard thereto. Blackstone. [ 1913 Webster ]

As science makes progress in any subject-matter, poetry recedes from it. J. H. Newman. [ 1913 Webster ]