Where does this definition of letter book come from?
This entry for letter book is sourced from GetWord Corpus, one of the dictionaries and corpora merged into Lughet.
Is letter book a noun, verb, or something else?
In this entry, letter book 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.