: Red words are intended for productive use (speaking and writing), whereas "black words" in the dictionary are primarily for receptive understanding (reading and listening).
Linguists have long debated how many words a person needs to "know" a language. Research suggests that while the English language contains over a million words, a surprisingly small number do the heavy lifting. Functional Fluency: At 2,500 words, a learner can survive. The "Magic" Number: macmillan 7500 words list pdf
The Macmillan list famously divides these 7,500 words into : : Red words are intended for productive use
The Oxford list is excellent for high school English. The Macmillan list is superior for university preparation and professional fluency because it includes the "long tail" of academic vocabulary. macmillan 7500 words list pdf