This Bites

I recently found this definition in Dictionary.com: 

 

plate tectonics

 

a theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under, or move past adjacent plates. 

Believe it or not, there is a similar definition found in the book of dentistry:

plate tectonics
 

a natural occurrence that will ensure the purchase of a summer home in the Hamptons. Clientele of a certain age will experience teeth shifting like tectonic plates. Offer them the option of Invisalign or standard braces. Explain that with age teeth are prone to independently collide with or slide under or move past adjacent gum lines. Use grave concern when saying lines like "It will only get worse". AARP Advertising highly advised.