BIP39 stands for Bitcoin Advancement Proposal 39. The words are selected from a certain list of 2048 frequent English words which can be utilized to the make a binary seed (your private key). Standard recovery phrases use a specific list of 2048 words pursuing the BIP39 standard (Bitcoin Improvement Proposal https://enrollbookmarks.com/story18779978/the-2-minute-rule-for-bip39-all-words