REDUNDANT: “exceeding what is necessary or normal: superfluous” — Merriam-Webster Online
CNN.com | June 18, 2010: So now you’re abandoned and redundant, wondering whether it’s OK to go see the latest Pixar without a youngster in hand. Yes, it’s OK; you owe it to yourself.
Are you redundant if your children are grown? No, even if you’re the [...]

CNN.com | July 21, 2010: “One man’s duplication is another man’s competitive analysis,” Clapper said of the newspaper’s assertion that there are excessive redundancies within the nation’s intelligence agencies.
CNN.com | July 19, 2010: We work constantly to reduce inefficiencies and redundancies, while preserving a degree of intentional overlap among agencies to strengthen analysis, challenge conventional thinking, and [...]

IMPEDANCE MISMATCH: “In the field of electronics, Impedance matching is the practice of designing the input impedance of an electrical load or the output impedance of its corresponding signal source in order to maximize the power transfer and minimize reflections from the load.” — from Wikipedia’s entry for impedance matching
If you don’t understand this definition (and I don’t), you have no business [...]