Replace seed by a most appropriate term in some occurrences

- Replace 'seed' by 'random sequence' twice, as using the term 'seed' to refer to the initial random sequence or value encoded by the mnemonic words is confusing, as these mnemonic words are later on used to derive the real 512-bit seed.
- Introduced the term "initial seed" to clarify that the "mnemonic" random sequence (entropy) can be considered, in fact, a seed, but to avoid confusion with the root seed, or seed, used later.
- Replace 'seed' by 'mnemonic code' twice, when covering the optional passphrase in BIP-39, as the mnemonic code plus the optional passphrase is what produces the seed. It is confusing if the term seed is used to refer to the initial entropy, rather than the 512-bit seed.
- All these modifications have been carefully evaluated to minimise the number of changes and leave the original usage of the (root) seed.

ch05.asciidoc

@@ -26,7 +26,7 @@ Bitcoin wallets contain keys, not coins. Each user has a wallet containing keys.
 
 ((("deterministic wallets", seealso="wallets")))The second type of wallet is a _deterministic wallet_, where all the keys are derived from a single master key, known as the _seed_. All the keys in this type of wallet are related to each other and can be generated again if one has the original seed. ((("key derivation methods")))There are a number of different _key derivation_ methods used in deterministic wallets. ((("hierarchical deterministic (HD) wallets", seealso="wallets")))The most commonly used derivation method uses a tree-like structure and is known as a _hierarchical deterministic_ or _HD_ wallet.
 
-((("mnemonic code words")))Deterministic wallets are initialized from a seed. To make these easier to use, seeds are encoded as English words, also known as _mnemonic code words_.
+((("mnemonic code words")))Deterministic wallets are initialized from a random sequence (entropy). To make these easier to use, random sequences are encoded as English words, also known as _mnemonic code words_.
 
 The next few sections introduce each of these technologies at a high level.
 
@@ -37,7 +37,7 @@ The next few sections introduce each of these technologies at a high level.
 
 [TIP]
 ====
-The use of nondeterministic wallets is discouraged for anything other than simple tests. They are simply too cumbersome to back up and use. Instead, use an industry-standard–based _HD wallet_ with a _mnemonic_ seed for backup.
+The use of nondeterministic wallets is discouraged for anything other than simple tests. They are simply too cumbersome to back up and use. Instead, use an industry-standard–based _HD wallet_ with a _mnemonic_ random sequence (entropy, or "initial seed") for backup.
 ====
 
 [[Type0_wallet]]
@@ -57,7 +57,7 @@ image::images/mbc2_0502.png["Deterministic Wallet"]
 [[hd_wallets]]
 ==== HD Wallets (BIP-32/BIP-44)
 
-((("wallets", "types of", "hierarchical deterministic (HD) wallets")))((("hierarchical deterministic (HD) wallets")))((("bitcoin improvement proposals", "Hierarchical Deterministic Wallets (BIP-32/BIP-44)")))Deterministic wallets were developed to make it easy to derive many keys from a single "seed." The most advanced form of deterministic wallets is the HD wallet defined by the BIP-32 standard. HD wallets contain keys derived in a tree structure, such that a parent key can derive a sequence of children keys, each of which can derive a sequence of grandchildren keys, and so on, to an infinite depth. This tree structure is illustrated in <<Type2_wallet>>.
+((("wallets", "types of", "hierarchical deterministic (HD) wallets")))((("hierarchical deterministic (HD) wallets")))((("bitcoin improvement proposals", "Hierarchical Deterministic Wallets (BIP-32/BIP-44)")))Deterministic wallets were developed to make it easy to derive many keys from a single "seed". The most advanced form of deterministic wallets is the HD wallet defined by the BIP-32 standard. HD wallets contain keys derived in a tree structure, such that a parent key can derive a sequence of children keys, each of which can derive a sequence of grandchildren keys, and so on, to an infinite depth. This tree structure is illustrated in <<Type2_wallet>>.
 
 [[Type2_wallet]]
 .Type-2 HD wallet: a tree of keys generated from a single seed
@@ -103,7 +103,7 @@ The following sections examine each of these technologies in detail.
 
 [TIP]
 ====
-If you are implementing a bitcoin wallet, it should be built as a HD wallet, with a seed encoded as mnemonic code for backup, following the BIP-32, BIP-39, BIP-43, and BIP-44 standards, as described in the following sections.
+If you are implementing a bitcoin wallet, it should be built as a HD wallet, with a seed derived from, and encoded as, a mnemonic code for backup, following the BIP-32, BIP-39, BIP-43, and BIP-44 standards, as described in the following sections.
 ====
 
 ==== Using a Bitcoin Wallet
@@ -116,7 +116,7 @@ If you are implementing a bitcoin wallet, it should be built as a HD wallet, wit
 .A Trezor device: a bitcoin HD wallet in hardware
 image::images/mbc2_0504.png[alt]
 
-When Gabriel used the Trezor for the first time, the device generated a mnemonic and seed from a built-in hardware random number generator. During this initialization phase, the wallet displayed a numbered sequence of words, one by one, on the screen (see <<trezor_mnemonic_display>>).
+When Gabriel used the Trezor for the first time, the device generated a random sequence (entropy), the associated mnemonic and derived a seed from a built-in hardware random number generator. During this initialization phase, the wallet displayed a numbered sequence of words, one by one, on the screen (see <<trezor_mnemonic_display>>).
 
 [[trezor_mnemonic_display]]
 .Trezor displaying one of the mnemonic words
@@ -277,9 +277,9 @@ The optional passphrase creates two important features:
 
 However, it is important to note that the use of a passphrase also introduces the risk of loss:
 
-* If the wallet owner is incapacitated or dead and no one else knows the passphrase, the seed is useless and all the funds stored in the wallet are lost forever.
+* If the wallet owner is incapacitated or dead and no one else knows the passphrase, the mnemonic code is useless and all the funds stored in the wallet are lost forever.
 
-* Conversely, if the owner backs up the passphrase in the same place as the seed, it defeats the purpose of a second factor.
+* Conversely, if the owner backs up the passphrase in the same place as the mnemonic code, it defeats the purpose of a second factor.
 
 While passphrases are very useful, they should only be used in combination with a carefully planned process for backup and recovery, considering the possibility of surviving the owner and allowing his or her family to recover the cryptocurrency estate.