nf11 this is an indicator of frequency-of-use ranking in the wordfreq file. "xx" is the number of the set of 500 words in which the entry can be found, with "01" assigned to the first 500, "02" to the second, and so on.
nf21 this is an indicator of frequency-of-use ranking in the wordfreq file. "xx" is the number of the set of 500 words in which the entry can be found, with "01" assigned to the first 500, "02" to the second, and so on.