Where does this definition of polite letters come from?
This entry for polite letters is sourced from GetWord Corpus, one of the dictionaries and corpora merged into Lughet.
Is polite letters a noun, verb, or something else?
In this entry, polite letters is tagged as 2n..
What is Lughet?
Lughet is a free trilingual dictionary covering nearly five million entries across Uyghur, Chinese, and English, drawn from more than ten source dictionaries and corpora.