Difficulty, Network Difficulty
This definition comes from the technical glossary.
Definition
How difficult it is to find a block relative to the difficulty of finding the easiest possible block. The easiest possible block has a proof-of-work difficulty of 1.
Synonyms
- 
    Difficulty 
- 
    Network difficulty 
Not To Be Confused With
- Target threshold (the value from which difficulty is calculated)
Links
- 
    Difficulty — Developer Guide 
- 
    Difficulty — Bitcoin Wiki 
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    How is difficulty calculated? — Bitcoin StackExchange