—peak /piːk/
adjective [before noun]
F0 peak times are the times when most people are using or doing something:
» Traffic congestion is really bad at peak periods (= when it is most busy).» It is most expensive to advertise at peak viewing times (= those with the most people watching).» Don't go there in the peak (= busiest) season - it'll be hot and crowded.Thesaurus+: ↑Busy and active , ↑Hurrying and doing things quicklyF0 peak levels or rates are when they are at their highest:
» peak rate electricityThesaurus+: ↑Maximum and minimumnoun [C] (HIGHEST POINT)
► B2 the highest, strongest, or best point, value, or level of skill: » Holiday flights reach a peak during August.» Beat the egg whites until they are stiff enough to form firm peaks.» We saw a victory by an athlete at the very peak of her fitness and career.Thesaurus+: ↑Higher and lower points of achievement , ↑Success and achievements , ↑Failures• • •
Extra Examples:» He seems to have reached the peak of his tennis career.» Accommodation is tricky to find at the peak of the season.» The evening rush hour reaches its peak between 5 and 6pm.» There are always peaks and troughs in any relationship.» The Beatles were at their peak during the 1960s.noun [C] (MOUNTAIN)
► B1 the pointed top of a mountain, or the mountain itself: » It is one of the most difficult peaks to climb.Thesaurus+: ↑Hills and mountains• • •
Extra Examples:» the glaciated peaks of the Himalayas» From the lowlands of the south to the rugged peaks in the north, Derbyshire has something for everyone.» Snow-covered peaks form a back-drop to beautiful mountain lakes.» Ben Nevis is Scotland's highest peak.» We set up camp three quarters of the way up the peak.noun [C] MAINLY UK (US USUALLY visor) (HAT PART)
► F0 the flat curved part of a cap which goes above the eyes of the person who is wearing itSee picture: peak 
Thesaurus+: ↑Things worn to cover the head, face or neck
verb [I] ↑Verb Endings for peak
► F0 to reach the highest, strongest, or best point, value, or level of skill: » Official figures show that unemployment peaked in November.Thesaurus+: ↑Higher and lower points of achievement , ↑Success and achievements , ↑Failures