BIP39 stands for Bitcoin Advancement Proposal 39. The words are chosen from a specific list of 2048 typical English words that may be used to the generate a binary seed (your non-public important). Standard recovery phrases use a specific list of 2048 words following the BIP39 standard (Bitcoin Advancement Proposal https://bookmark-search.com/story18809831/how-much-you-need-to-expect-you-ll-pay-for-a-good-bip39-definition