BIP39 means Bitcoin Advancement Proposal 39. The words are selected from a specific list of 2048 common English words that may be utilized to the produce a binary seed (your private key). Standard recovery phrases use a particular list of 2048 words pursuing the BIP39 standard (Bitcoin Improvement Proposal 39). https://bookmarkmiracle.com/story20570807/the-invalid-bip39-phrase-diaries