** In order theory, see order automorphism.

** Microevolution: species — speciation — adaptation — selection — natural selection — directional selection — sexual selection — genetic drift — sexual reproduction — asexual reproduction — colony — allele frequency — neutral theory of molecular evolution — population genetics — Hardy-Weinberg principle

** Quantum chromodynamics, a theory of the strong interaction ( color force )

** Dual ( category theory ), a formalization of mathematical duality

** LTI system theory

** electron theory of metals

** Backward induction in game theory and economics

** for his profound contributions to three major areas of operations research and management science: inventory theory, dynamic programming and lattice programming.

** in recognition of his fundamental contributions to game theory and related areas

** for his contributions to queueing theory, applied probability and stochastic modelling

** Limit ( category theory )

** Most forms of cognitivism hold that some such propositions are true, as opposed to error theory, which asserts that all are erroneous.

** Error theory, another form of moral anti-realism, holds that although ethical claims do express propositions, all such propositions are false.

** In topos theory, the ( codomain of the ) subobject classifier of an elementary topos.

** In group theory, the omega and agemo subgroups of a p-group, Ω ( G ) and ℧( G )

** In number theory, Ω ( n ) is the number of prime divisors of n.

** In relational database theory to represent NULL, a missing or inapplicable value.

** In set theory, the first uncountable ordinal number ( more commonly written as ω < sub > 1 </ sub >)

** In number theory, ω ( n ) is the number of distinct prime divisors of n.

** In number theory, an arithmetic function

** the ultraproduct, in model theory.

** General relativity, Albert Einstein's theory of gravitation

** Special relativity, a theory formulated by Albert Einstein, Henri Poincaré, and Hendrik Lorentz

** Constructionism ( learning theory )

** Coherence theory of truth

** SBA / ATT — Stolen base attempts: total number of times the player has attempted to steal a base ( SB + CS )

** The Marquis in The Romance of the Forest – attempts to get with Adeline even though he is already married, attempts to rape Adeline, blackmails Monsieur LaMotte.

** Mediation attempts in the 2011-2012 Yemeni uprising since c. 2011

** The U. S. Army 36th Infantry Division, in Italy, attempts to cross the Rapido River.

** Hideki Tōjō, Japanese prime minister during most of WWII, attempts suicide to avoid facing a war crimes tribunal.

** Thirty Years ' War: Chased by the Count of Tilly's army, Christian of Brunswick's army attempts to flee to the Dutch Republic.

** In Sacramento, California, Lynette Fromme, a follower of jailed cult leader Charles Manson, attempts to assassinate U. S. President Gerald Ford, but is thwarted by a Secret Service agent.

** Tiberius Sempronius Gracchus, Roman politician, who, as a plebeian tribune, will cause political turmoil in the Republic through his attempts to legislate agrarian reforms ; his political ideals will eventually lead to his death at the hands of supporters of the conservative faction ( Optimates ) of the Roman Senate ( d. 132 BC )

** Wildlife management – attempts to balance the needs of wildlife with the needs of people using the best available science.

** The National Indian Gaming Association has criticized Benedict's book, accusing it of being a work of fiction which attempts to undermine the tribe's status as an Indian nation.

** After eleven failed attempts, the skateboarder Tony Hawk finally landed a 900-degree spin ( the 900 ).

** Shaun White failed to land the 1080 in skate best trick after 29 attempts.

** Jeaux Hall landed the 1080 in the half-pipe contest after 17 attempts

** May 11 – Battle of Cienfuegos ; US to cuts telegraph cable at Cienfuegos after two failed attempts ( I )

** June 30 – First Battle of Manzanillo ; a US naval force attempts to clear the harbor but is repulsed ( S )

** Theodicy – attempts at reconciling the existence of evil and suffering in the world with the nature and justice of God

** kicks or attempts to kick an opponent ;

** trips or attempts to trip an opponent ;

** The U. S. Army Air Forces Eighth Air Force attempts a raid by 857 bombers escorted by 678 fighters against industrial and transportation targets in Germany, but all the bombers are grounded or recalled due to bad weather except for 58 which hit a power station near Eschweiler.

** Samuel Byck attempts to hijack Delta Airlines Flight 523, a Douglas DC-9, before it leaves the gate at Baltimore-Washington International Airport, with a goal of crashing it into the White House in Washington, D. C. to assassinate U. S. President Richard Nixon.

** In Operation Niki, Greeces Hellenic Air Force attempts a covert airlift of a battalion of Greek commandos from Souda, Crete, to Cyprus using 15 Noratlas aircraft.

** Revision control utilities are intended to deal with situations where more than one user attempts to simultaneously modify the same file.

** " Undertow "-Kane's mistress attempts to escape from him