diff --git a/polkadot/runtime/kusama/src/constants.rs b/polkadot/runtime/kusama/src/constants.rs
index 6b60cb1c9aab6fe988d8020551c01552ffd9ff0d..13efedea0bed407baecad3d4f621e68398077274 100644
--- a/polkadot/runtime/kusama/src/constants.rs
+++ b/polkadot/runtime/kusama/src/constants.rs
@@ -37,11 +37,11 @@ pub mod time {
 //	pub const MILLISECS_PER_BLOCK: Moment = 1000;
 	pub const SLOT_DURATION: Moment = MILLISECS_PER_BLOCK;
 	// Kusama
-	pub const EPOCH_DURATION_IN_BLOCKS: BlockNumber = 1 * HOURS;
+	pub const EPOCH_DURATION_IN_SLOTS: BlockNumber = 1 * HOURS;
 	// Mainnet
-//	pub const EPOCH_DURATION_IN_BLOCKS: BlockNumber = 4 * HOURS;
+//	pub const EPOCH_DURATION_IN_SLOTS: BlockNumber = 4 * HOURS;
 	// Testnet
-//	pub const EPOCH_DURATION_IN_BLOCKS: BlockNumber = 10 * MINUTES;
+//	pub const EPOCH_DURATION_IN_SLOTS: BlockNumber = 10 * MINUTES;
 
 	// These time units are defined in number of blocks.
 	pub const MINUTES: BlockNumber = 60_000 / (MILLISECS_PER_BLOCK as BlockNumber);
diff --git a/polkadot/runtime/kusama/src/lib.rs b/polkadot/runtime/kusama/src/lib.rs
index a31683d81d4826b2998624ddc0cebf19bd254e5d..a931677000f01d335738324fc421bd268f7e8182 100644
--- a/polkadot/runtime/kusama/src/lib.rs
+++ b/polkadot/runtime/kusama/src/lib.rs
@@ -180,7 +180,7 @@ impl pallet_scheduler::Config for Runtime {
 }
 
 parameter_types! {
-	pub const EpochDuration: u64 = EPOCH_DURATION_IN_BLOCKS as u64;
+	pub const EpochDuration: u64 = EPOCH_DURATION_IN_SLOTS as u64;
 	pub const ExpectedBlockTime: Moment = MILLISECS_PER_BLOCK;
 	pub const ReportLongevity: u64 =
 		BondingDuration::get() as u64 * SessionsPerEra::get() as u64 * EpochDuration::get();
@@ -311,7 +311,7 @@ impl pallet_session::historical::Config for Runtime {
 parameter_types! {
 	// no signed phase for now, just unsigned.
 	pub const SignedPhase: u32 = 0;
-	pub const UnsignedPhase: u32 = EPOCH_DURATION_IN_BLOCKS / 4;
+	pub const UnsignedPhase: u32 = EPOCH_DURATION_IN_SLOTS / 4;
 
 	// fallback: run election on-chain.
 	pub const Fallback: pallet_election_provider_multi_phase::FallbackStrategy =
diff --git a/polkadot/runtime/polkadot/src/constants.rs b/polkadot/runtime/polkadot/src/constants.rs
index 6b72b7e921001e84a5db8cbd3e1836de0d22bbc0..27a674fe9b4f1e9f54c631b87ad0c7746ba3fdd7 100644
--- a/polkadot/runtime/polkadot/src/constants.rs
+++ b/polkadot/runtime/polkadot/src/constants.rs
@@ -33,7 +33,7 @@ pub mod time {
 	use primitives::v0::{Moment, BlockNumber};
 	pub const MILLISECS_PER_BLOCK: Moment = 6000;
 	pub const SLOT_DURATION: Moment = MILLISECS_PER_BLOCK;
-	pub const EPOCH_DURATION_IN_BLOCKS: BlockNumber = 4 * HOURS;
+	pub const EPOCH_DURATION_IN_SLOTS: BlockNumber = 4 * HOURS;
 
 	// These time units are defined in number of blocks.
 	pub const MINUTES: BlockNumber = 60_000 / (MILLISECS_PER_BLOCK as BlockNumber);
diff --git a/polkadot/runtime/polkadot/src/lib.rs b/polkadot/runtime/polkadot/src/lib.rs
index e2967b77898d263fee6f4ee17b2307360c22fe8e..5b0665e9bf428fc453465b18581fd437f1520070 100644
--- a/polkadot/runtime/polkadot/src/lib.rs
+++ b/polkadot/runtime/polkadot/src/lib.rs
@@ -194,7 +194,7 @@ impl pallet_scheduler::Config for Runtime {
 }
 
 parameter_types! {
-	pub const EpochDuration: u64 = EPOCH_DURATION_IN_BLOCKS as u64;
+	pub const EpochDuration: u64 = EPOCH_DURATION_IN_SLOTS as u64;
 	pub const ExpectedBlockTime: Moment = MILLISECS_PER_BLOCK;
 	pub const ReportLongevity: u64 =
 		BondingDuration::get() as u64 * SessionsPerEra::get() as u64 * EpochDuration::get();
@@ -321,7 +321,7 @@ impl pallet_session::historical::Config for Runtime {
 parameter_types! {
 	// no signed phase for now, just unsigned.
 	pub const SignedPhase: u32 = 0;
-	pub const UnsignedPhase: u32 = EPOCH_DURATION_IN_BLOCKS / 4;
+	pub const UnsignedPhase: u32 = EPOCH_DURATION_IN_SLOTS / 4;
 
 	// fallback: run election on-chain.
 	pub const Fallback: pallet_election_provider_multi_phase::FallbackStrategy =
diff --git a/polkadot/runtime/test-runtime/src/constants.rs b/polkadot/runtime/test-runtime/src/constants.rs
index 0d9a4fa088e3aa16d6d8b744c8ede8aa5f9f983a..658a4bdca7a0115dd2df253f81f533063ff883e5 100644
--- a/polkadot/runtime/test-runtime/src/constants.rs
+++ b/polkadot/runtime/test-runtime/src/constants.rs
@@ -31,7 +31,7 @@ pub mod time {
 	pub const MILLISECS_PER_BLOCK: Moment = 6000;
 	pub const SLOT_DURATION: Moment = MILLISECS_PER_BLOCK;
 	// 30 seconds for now
-	pub const EPOCH_DURATION_IN_BLOCKS: BlockNumber = MINUTES / 2;
+	pub const EPOCH_DURATION_IN_SLOTS: BlockNumber = MINUTES / 2;
 
 	// These time units are defined in number of blocks.
 	pub const MINUTES: BlockNumber = 60_000 / (MILLISECS_PER_BLOCK as BlockNumber);
diff --git a/polkadot/runtime/test-runtime/src/lib.rs b/polkadot/runtime/test-runtime/src/lib.rs
index fd5253fe21fd6555e33396d324d70a95aac4f130..2a0cc386af548ce7ca63c0a5f3ef26abdd65160d 100644
--- a/polkadot/runtime/test-runtime/src/lib.rs
+++ b/polkadot/runtime/test-runtime/src/lib.rs
@@ -162,7 +162,7 @@ impl<C> frame_system::offchain::SendTransactionTypes<C> for Runtime where
 }
 
 parameter_types! {
-	pub storage EpochDuration: u64 = EPOCH_DURATION_IN_BLOCKS as u64;
+	pub storage EpochDuration: u64 = EPOCH_DURATION_IN_SLOTS as u64;
 	pub storage ExpectedBlockTime: Moment = MILLISECS_PER_BLOCK;
 }
 
diff --git a/polkadot/runtime/westend/src/constants.rs b/polkadot/runtime/westend/src/constants.rs
index b897299ed45e3c8d1cd0f05326e754c40825df67..08eaa8dcb453d32367838c275a81b093d8c22043 100644
--- a/polkadot/runtime/westend/src/constants.rs
+++ b/polkadot/runtime/westend/src/constants.rs
@@ -33,7 +33,7 @@ pub mod time {
 	use primitives::v0::{Moment, BlockNumber};
 	pub const MILLISECS_PER_BLOCK: Moment = 6000;
 	pub const SLOT_DURATION: Moment = MILLISECS_PER_BLOCK;
-	pub const EPOCH_DURATION_IN_BLOCKS: BlockNumber = 1 * HOURS;
+	pub const EPOCH_DURATION_IN_SLOTS: BlockNumber = 1 * HOURS;
 
 	// These time units are defined in number of blocks.
 	pub const MINUTES: BlockNumber = 60_000 / (MILLISECS_PER_BLOCK as BlockNumber);
diff --git a/polkadot/runtime/westend/src/lib.rs b/polkadot/runtime/westend/src/lib.rs
index a272abe0508e4b7f156282a135470031d617c3da..18f605fdf31cfd73cccfdac5ef5935ad6a01c32c 100644
--- a/polkadot/runtime/westend/src/lib.rs
+++ b/polkadot/runtime/westend/src/lib.rs
@@ -172,7 +172,7 @@ impl pallet_scheduler::Config for Runtime {
 }
 
 parameter_types! {
-	pub const EpochDuration: u64 = EPOCH_DURATION_IN_BLOCKS as u64;
+	pub const EpochDuration: u64 = EPOCH_DURATION_IN_SLOTS as u64;
 	pub const ExpectedBlockTime: Moment = MILLISECS_PER_BLOCK;
 	pub const ReportLongevity: u64 =
 		BondingDuration::get() as u64 * SessionsPerEra::get() as u64 * EpochDuration::get();
@@ -337,7 +337,7 @@ impl pallet_session::historical::Config for Runtime {
 parameter_types! {
 	// no signed phase for now, just unsigned.
 	pub const SignedPhase: u32 = 0;
-	pub const UnsignedPhase: u32 = EPOCH_DURATION_IN_BLOCKS / 4;
+	pub const UnsignedPhase: u32 = EPOCH_DURATION_IN_SLOTS / 4;
 
 	// fallback: run election on-chain.
 	pub const Fallback: pallet_election_provider_multi_phase::FallbackStrategy =