defense

American  

[dih-fens, dee-fens] / dɪˈfɛns, ˈdi fɛns /

noun

1. resistance against attack; protection.

   Two more regiments are needed for the defense of the city.

   Synonyms:

   safeguard, security

2. something that guards against harm, such as a fortification, physical or mental quality, or medication.

   This fort was once the main defense of the island.

3. the support of a cause or the like by speech, argument, etc..

   He spoke in defense of the nation's foreign policy.

   Synonyms:

   justification, advocacy, support

4. a speech, argument, etc., in vindication.

   She delivered a defense of free enterprise.

5. Law.

   1. the denial or pleading of the defendant in answer to the claim or charge that has been made.

   2. the proceedings adopted by a defendant or the defendant's legal agents, for defending against the charges that have been made.

   3. a defendant and their counsel.

6. Psychology. defense mechanism.

7. Sports.

   1. the practice or art of shielding oneself or one's goal from attack, as in fencing, boxing, soccer, or football.

   2. the team attempting to thwart the attack of the team having the ball or puck.

   3. the players of a team who line up in their own defensive zone.

   4. the positions on the field, ice, etc., taken by such players.

8. Also called Defense Department.  (initial capital letter) the Department of Defense.

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verb (used with object)

defensed, defensing

1. Sports. to defend against (an opponent, play, or tactic).

Other Word Forms

• defenseless adjective
• defenselessly adverb
• defenselessness noun
• nondefense noun
• predefense noun
• undefensed adjective

Etymology

Origin of defense

First recorded in 1250–1300; Middle English from Old French from Late Latin dēfēnsa “a forbidding,” noun use of feminine of past participle of Latin dēfendere “to defend ”; replacing Middle English defens, from Anglo-French, Old French, from Medieval Latin defēnsum “(thing) forbidden,” neuter past participle of Latin dēfendere

Example Sentences

The episode exposed a fault line in Silicon Valley between engineers who viewed autonomous targeting as an ethical red line and defense officials who saw it as essential.

From Barron's • Apr. 5, 2026

How do we score, how do we score efficiently, and our defense again is, it’s we’re interchangeable.

From Los Angeles Times • Apr. 4, 2026

After finishing the accelerator program, which counts OpenAI chief Sam Altman among its graduates, Rhodes-Kropf, 21, raised $5 million for his defense tech startup, SalesPatriot.

From The Wall Street Journal • Apr. 4, 2026

For 2027, President Donald Trump is asking for a record military defense budget of $1.5 trillion as part of the White House’s proposed budget plan.

From Salon • Apr. 3, 2026

“Squid have two lines of defense: squirting ink and escaping quickly. They need a lot of oxygen to move away from predators. Maybe they have three hearts to keep up the oxygen supply.”

From "The Line Tender" by Kate Allen