diff --git a/spec/abci/abci.md b/spec/abci/abci.md
index 5c704be27..10170c4e3 100644
--- a/spec/abci/abci.md
+++ b/spec/abci/abci.md
@@ -69,26 +69,26 @@ Example:
  Events: []abci.Event{
   {
    Type: "validator.provisions",
-   Attributes: kv.Pairs{
-    kv.Pair{Key: []byte("address"), Value: []byte("...")},
-    kv.Pair{Key: []byte("amount"), Value: []byte("...")},
-    kv.Pair{Key: []byte("balance"), Value: []byte("...")},
+   Attributes: []abci.EventAttribute{
+    abci.EventAttribute{Key: []byte("address"), Value: []byte("..."), Index: true},
+    abci.EventAttribute{Key: []byte("amount"), Value: []byte("..."), Index: true},
+    abci.EventAttribute{Key: []byte("balance"), Value: []byte("..."), Index: true},
    },
   },
   {
    Type: "validator.provisions",
-   Attributes: kv.Pairs{
-    kv.Pair{Key: []byte("address"), Value: []byte("...")},
-    kv.Pair{Key: []byte("amount"), Value: []byte("...")},
-    kv.Pair{Key: []byte("balance"), Value: []byte("...")},
+   Attributes: []abci.EventAttribute{
+    abci.EventAttribute{Key: []byte("address"), Value: []byte("..."), Index: true},
+    abci.EventAttribute{Key: []byte("amount"), Value: []byte("..."), Index: false},
+    abci.EventAttribute{Key: []byte("balance"), Value: []byte("..."), Index: false},
    },
   },
   {
    Type: "validator.slashed",
-   Attributes: kv.Pairs{
-    kv.Pair{Key: []byte("address"), Value: []byte("...")},
-    kv.Pair{Key: []byte("amount"), Value: []byte("...")},
-    kv.Pair{Key: []byte("reason"), Value: []byte("...")},
+   Attributes: []abci.EventAttribute{
+    abci.EventAttribute{Key: []byte("address"), Value: []byte("..."), Index: false},
+    abci.EventAttribute{Key: []byte("amount"), Value: []byte("..."), Index: true},
+    abci.EventAttribute{Key: []byte("reason"), Value: []byte("..."), Index: true},
    },
   },
   // ...
@@ -305,7 +305,7 @@ via light client.
     - `ByzantineValidators ([]Evidence)`: List of evidence of
     validators that acted maliciously.
 - **Response**:
-    - `Tags ([]kv.Pair)`: Key-Value tags for filtering and indexing
+    - `Events ([]abci.Event)`: Type & Key-Value events for indexing
 - **Usage**:
     - Signals the beginning of a new block. Called prior to
     any DeliverTxs.
@@ -332,7 +332,7 @@ via light client.
     be non-deterministic.
     - `GasWanted (int64)`: Amount of gas requested for transaction.
     - `GasUsed (int64)`: Amount of gas consumed by transaction.
-    - `Tags ([]kv.Pair)`: Key-Value tags for filtering and indexing
+    - `Events ([]abci.Event)`: Type & Key-Value events for indexing
     transactions (eg. by account).
     - `Codespace (string)`: Namespace for the `Code`.
 - **Usage**:
@@ -360,7 +360,7 @@ via light client.
     be non-deterministic.
     - `GasWanted (int64)`: Amount of gas requested for transaction.
     - `GasUsed (int64)`: Amount of gas consumed by transaction.
-    - `Tags ([]kv.Pair)`: Key-Value tags for filtering and indexing
+    - `Events ([]abci.Event)`: Type & Key-Value events for indexing
     transactions (eg. by account).
     - `Codespace (string)`: Namespace for the `Code`.
 - **Usage**:
@@ -377,7 +377,7 @@ via light client.
     voting power to 0 to remove).
     - `ConsensusParamUpdates (ConsensusParams)`: Changes to
     consensus-critical time, size, and other parameters.
-    - `Tags ([]kv.Pair)`: Key-Value tags for filtering and indexing
+    - `Events ([]abci.Event)`: Type & Key-Value events for indexing
 - **Usage**:
     - Signals the end of a block.
     - Called after all transactions, prior to each Commit.
diff --git a/spec/abci/apps.md b/spec/abci/apps.md
index da13962eb..860404096 100644
--- a/spec/abci/apps.md
+++ b/spec/abci/apps.md
@@ -196,7 +196,7 @@ not broadcasted to other peers and not included in a proposal block.
 `Data` contains the result of the CheckTx transaction execution, if any. It is
 semantically meaningless to Tendermint.
 
-`Tags` include any tags for the execution, though since the transaction has not
+`Events` include any events for the execution, though since the transaction has not
 been committed yet, they are effectively ignored by Tendermint.
 
 ### DeliverTx
diff --git a/spec/core/state.md b/spec/core/state.md
index 375118b23..6b12ba4a9 100644
--- a/spec/core/state.md
+++ b/spec/core/state.md
@@ -68,7 +68,7 @@ type Result struct {
 It returns a result code and an arbitrary byte array (ie. a return value).
 
 NOTE: the Result needs to be updated to include more fields returned from
-processing transactions, like gas variables and tags - see
+processing transactions, like gas variables and events - see
 [issue 1007](https://github.com/tendermint/tendermint/issues/1007).
 
 ### Validator