A technical term combining the ideas of difference and frequency.  Now used in regards to the predictable unpredictability of individuals – particularly women.  The term has its origins in the writings of Daniel Webster the Elder who was the godfather and inspiration for the name of the famed lawyer and American Revolutionary war figure. 

1.  The problem for planning a maintenance schedule is that we know customers will be very differency in the usage. 

2.  I don't know what to get them for Christmas, you know they all have to have their differency even if they are sisters. 

3.  It isn't that he isn't fabulous.  Fashion just hasn't caught up with his differency yet.