What is the definition of the word multiplicity in the context of a patent?

Answer 1

Any number greater than one. "Plurality" means "two or more".

For example, a patent claim may include an element worded as, "a widget for nobulating, including a plurality of smurfs..." This means that a similarly nobulating widget with a single smurf would not literally infringe this element, but an example with two, three, or even six hundred smurfs could.

The context of the invention disclosure could also limit the actual number in a particular plurality.

Example: a statement that "each corner has one smurf" and another statement that "there can only be up to five corners." In this case, "plurality" effectively means 2, 3, 4, or 5 and the patentee would have a harder time proving literal infringement if another inventor comes up with a way to nobulate with six or more corners. This is because the disclosure has (perhaps inadvertently) "given away" the fact that this patent does not even envision having more than five corners (or smurfs), and you can't claim what you haven't yet invented.

A safer way to word it might have been, "a suitable embodiment of the invention has been found to function well with up to five corners, and one smurf per corner, although other functional combinations will also be apparent to those skilled in the art." Thus, the claimed "plurality" would have the broadest possible meaning, "two or more". A condition of suffering or disease--- APEX

Answer 2

A patent application needs to specify precisely what the "invention" is, but there can be more than one "invention" in a given patent claim. Say I want to patent my new washing machine: I can have the way it uses less water and the way it is less damaging to clothing in the same patent, as multiple claims.

Undue multiplicity would be trying to divide up the inventive steps into more pieces than is necessary, in order to have more claims.