BIP39 stands for Bitcoin Improvement Proposal 39. The words are picked from a selected list of 2048 popular English words which can be used to the produce a binary seed (your private important). Standard recovery phrases use a specific list of 2048 words following the BIP39 standard (Bitcoin Enhancement Proposal https://socialupme.com/story5031640/the-fact-about-valid-bip39-seed-phrase-that-no-one-is-suggesting