From Longman Dictionary of Contemporary Englishmark somebody/something ↔ down phrasal verb1WRITEto write something down, especially in order to keep a recordMark down everything you eat on your daily chart.mark somebody/something down as somethingThe teacher marked him down as absent.2CHEAPto reduce the price of something opp mark up → markdownWinter coats have been marked down from $80 to $50.3RESULT/GRADE especially British English to give a student a lower result in a test, paper etc because they have made mistakesStudents will be marked down for failing to follow directions. →mark→ See Verb table
Examples from the Corpus
mark down• I could accept the decision by the Referees' Committee if my marks had gone down.• You and Al will be marked.• He marked Franklin down as 5/20.• On the 12 May, a SeaKingmark 5 went down at 50o 53'S, 54o 40'W.• It was quoted at 1. 4359 marks, down from 1. 4370 marks in New York.• It was quoted at 1. 4655 marks, down from 1. 4675 marks in late New York tradingyesterday.• It fell as low as 72. 41 marks, down from 72. 77 yen in late New York trading Tuesday.mark somebody/something down as something• He marked Franklin down as 5/20.