"Peak oil": 1. The maximum global total rate of oil extraction and the date of the maximum rate. When global Peak oil extraction has passed, global total oil usage must also necessarily decline. Opinions vary about whether global Peak oil will occur in the near future, or whether it has already passed. 2. The similarly defined rate and date in relation to a smaller entity, for example an individual country. 3. A shorthand term summarising the impossibility of basing long term sustainable growth on finite physical resources.