Rule of three

Rule of three or Rule of Thirds may refer to:

Science and technology

 * Rule of three (aeronautics), a rule of descent in aviation
 * Rule of three (C++ programming), a rule of thumb about class method definitions
 * Rule of three (computer programming), a rule of thumb about code refactoring
 * Rule of three (hematology), a rule of thumb to check if blood count results are correct
 * Rule of three (mathematics), a method in arithmetic
 * Rule of three (medicinal chemistry), a rule of thumb for lead-like compounds
 * Rule of three (statistics), for calculating a confidence limit when no events have been observed
 * Rule of threes (survival), the rule of threes involves the priorities in order to survive

Arts and entertainment

 * Rule of Three, a podcast by Jason Hazeley and Joel Morris
 * Rule of Three, a series of one-act plays by Agatha Christie
 * The Bellman's Rule of Three in The Hunting of the Snark, a poem by Lewis Carroll
 * The Rule of Thirds, a 2008 album by Death In June

Other Uses

 * Rule of threes (survival), the priorities in order to survive
 * Rule of Three (Wicca), a religious tenet
 * Rule of three (writing), a principle of writing, and of rhetoric

Variations

 * Rule of thirds, a rule of thumb for composing visual images
 * Rule of thirds (diving), a rule of thumb for divers
 * Rule of thirds (military), a rule of thumb in military planning