BIP39 stands for Bitcoin Improvement Proposal 39. The words are chosen from a particular list of 2048 common English words which can be accustomed to the make a binary seed (your non-public important). Standard recovery phrases use a selected list of 2048 words next the BIP39 standard (Bitcoin Advancement Proposal https://sparxsocial.com/story9305863/5-essential-elements-for-bip39-explained