Frankensteining is the merging of several parts into a single whole.
In design, Frankensteining is a combination of good elements from different concepts into one superconcept. Frankensteining is more commonly used in fashion design by mixing pieces of clothing from different outfits: one sleeve of this style, the second of another, and so on.
Frankensteining can be helpful to make something great and brand new. But it doesn't always work. Sometimes it can result in a poor design with no real identity. Be careful Frankensteining your design.