Where does this definition of back-door come from?
This entry for back-door is sourced from Main Dictionary, one of the dictionaries and corpora merged into Lughet.
Is back-door a noun, verb, or something else?
In this entry, back-door is tagged as adjective.
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.