- "in peak health" (#). This expression is so well known that a surprising number of medical facilities play on it (#)
- "at peak [commuter] hours" (#)
Peak oil is the point in time when the maximum rate of global petroleum extraction is reached ...
Peak in this sense seems to gobble up a bit more meaning than just "apex"; as used here, it seems to mean "upper limit of the (easy) availability of [commodity]." And sure enough, this usage can be generalized:
Where else do we see this usage?
Update 10/14/08: John Cole uses the term Peak Wingnut in a political blog, which is then deconstructed somewhat (mostly the "wingnut" part) by Mark Liberman on the Language Log under the title "Peak X."