BIP39 means Bitcoin Enhancement Proposal 39. The words are selected from a certain list of 2048 common English words which can be accustomed to the make a binary seed (your non-public critical). If you are unsure about a particular word's spelling, utilize the look for purpose (Ctrl+File on Windows/Command+F on https://infopagex.com/story4167595/the-greatest-guide-to-seed-phrase-bip39