1 (wiktionary) 2 (vi.wikipedia) 3 (en.wikipedia) 4 (glosbe)

Compounds Expand your vocabulary by studying more complex words built by the 'core words'.
Etymology Explore the origin of the 'core words'.
Wordsense Learn about the wordsenses of the english term.

TOPIK 11000 KOREAN WORDS

HSK 3.0 11000 CHINESE WORDS
4 填空  tián kòng to fill a job vacancy, to fill in a blank (e.g. on questionnaire or exam paper)

ENGLISH 6000 THEME WORDS

OXFORD 5000 CORE WORDS

TANAKA 6000 CORE WORDS