open
/ˈəʊpən/
Binary Representation
11-bit index: 10011011001 (decimal 1241)
Position
#1242 of 2048
Hex Index
0x4D9
4-Letter Prefix
open
About "open" in BIP39
"open" is the #1242 word
in the official BIP39 English mnemonic wordlist. It is encoded as the 11-bit binary value
10011011001
(decimal index 1241), placing it at the 61% mark of the full 2048-word list.
The 4-letter prefix "open" uniquely identifies this word among all 2048 entries. At just 4 characters, "open" is one of the shorter words in the BIP39 list, making it quicker to type during wallet recovery but potentially easier to confuse with similar short entries.
Located in the middle section of the wordlist (index 1241), "open" belongs to the "O" letter group, which contains 55 words. It is the #28 entry in that group. Mid-range words have a balanced mix of 0s and 1s in their binary representation.
In a 12-word seed phrase, each word encodes 11 bits of entropy. The probability of "open" appearing in any specific position of a randomly generated phrase is 1 in 2048 (≈ 0.049%). A complete 24-word phrase encodes 256 bits of entropy, providing security equivalent to a key space of approximately 1.16 × 10⁷⁷ — far beyond the reach of brute-force attacks.
Word #1242 in the Other 9 BIP39 Wordlists
Every official BIP39 wordlist has exactly 2048 entries, so index 1241 encodes the same 11-bit value
(10011011001) in every language.
A wallet configured for one of these languages would use this word instead of "open":
Similar Words — Check Carefully During Recovery
2 BIP39 words differ from "open" by just a single letter — the most common source of typos when a seed phrase is entered by hand:
Words sharing the first three letters "ope":
Reminder: the first 4 letters of every BIP39 word are unique across the whole list, so "open" always identifies "open".