BIP39 means Bitcoin Improvement Proposal 39. The words are picked from a certain list of 2048 typical English words that may be used to the create a binary seed (your private critical). Standard recovery phrases use a particular list of 2048 words subsequent the BIP39 standard (Bitcoin Advancement Proposal 39). https://bookmarkingalpha.com/story19150759/5-simple-techniques-for-bip39-word-list-pdf