BIP39 stands for Bitcoin Advancement Proposal 39. The words are picked from a certain list of 2048 prevalent English words which may be used to the generate a binary seed (your private key). This additional complexity boosts the hazard of misplacing the passphrase, and so losing your copyright. Based on https://linkedbookmarker.com/story4480610/helping-the-others-realize-the-advantages-of-bip39-mnemonic-phrase-tool