APEX

Multiple Entries:
  Apex    apex  

Concise Oxford English Dictionary © 2008 Oxford University Press:
Apex /ˈeɪpɛks/

▶noun a system of reduced fares for scheduled airline flights and railway journeys which must be booked and paid for in advance.

– origin 1970s: from Advance Purchase Excursion.

Concise Oxford English Dictionary © 2008 Oxford University Press:
apex /ˈeɪpɛks/

▶noun (pl. apexes or apices /ˈeɪpɪsiːz/)

• 1 the top or highest part of something, especially one forming a point.

  ■ Botany the growing point of a shoot.

• 2 the highest point of achievement.

▶verb reach a high point or climax.

– origin C17: from L., ‘peak, tip’.