An alphabetical list of 4,800 words is presented, each followed by the percentage of students in grades 11 and 13 who chose the correct definition in a series of three-choice vocabulary tests. Each percent is based on the number of students who completed the item, which averages 91 in grade 11, 74 in grade 13. Percentages in grade 11 were corrected for the deviation of each sample mean from the citywide mean based on 3,220 cases, which was found to be statistically defensible. No such correction in the college group was necessary, for sample means did not vary more than would be expected by chance. The words include all words from the sixth through the twentieth thousand in frequency of occurrence in Thorndike's Teacher's Word Book except proper names, technical terms, archaic and obsolete words, words certainly known from frequency in spoken English, simple compounds of words in the first five thousand and of other words that were tested in their simplest form, and a few words above 15,000 not likely to be generally useful. The list is believed to include all words above the first five thousand that are part of the general vocabulary, are not partial duplicates of one another, and are not certainly known by high school and college students, down to the level at which words occur less than once per million running words.