Merge branch 'develop' into patch-64

glossary.asciidoc

@@ -24,6 +24,9 @@ block reward (aka coinbase reward)::
 Byzantine Generals Problem::
     A reliable computer system must be able to cope with the failure of one or more of its components. A failed component may exhibit a type of behavior that is often overlooked--namely, sending conflicting information to different parts of the system. The problem of coping with this type of failure is expressed abstractly as the Byzantine Generals Problem.
 
+candidate block::
+	A block that a miner is still trying to mine. It is not yet a valid block, because it does not contain a valid Proof-of-Work.
+
 coinbase (aka coinbase data)::
 	A special field used as the sole input for coinbase transactions. The coinbase data field allows claiming the block reward and provides up to 100 bytes for arbitrary data.
 	Not to be confused with coinbase transaction or coinbase reward.
@@ -233,7 +236,8 @@ soft fork::
     Not to be confused with fork, hard fork, software fork or Git fork.
 
 stale block::
-    Block that was successfully mined but that isn’t included on the current best block chain, likely because some other block at the same height had its chain extended first. Not to be confused with orphan block.
+    A valid block that was successfully mined but that isn’t included on the current main branch (with most cumulative Proof-of-Work), because some other valid block that was mined at the same height had its chain extended first. The miner of a stale block doesn't get the block reward or the transactions fees of this block. 
+    Not to be confused with orphan block or candidate block.
 
 timelocks::
     A timelock is a type of encumbrance that restricts the spending of some bitcoin until a specified future time or block height. Timelocks feature prominently in many Bitcoin contracts, including payment channels and hashed timelock contracts.