The Commens Dictionary
Quote from ‘On Logical Graphs’
…let a number of the proper designations of individual subjects be omitted, so that the assertion becomes a mere blank form for an assertion which can be reconverted into an assertion by filling all the blanks with proper names. I term such a blank form a rheme. [—] If the number of blanks exceeds one, I term it a Relative Rheme. If the number of blanks is two, I term the rheme a Dyad, or Dyadic Relative.
‘Dyad’ (pub. 12.01.15-16:08). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from http://www.commens.org/dictionary/entry/quote-logical-graphs-2.