reciprocal

American  

[ri-sip-ruh-kuhl] / rɪˈsɪp rə kəl /

adjective

1. given or felt by each toward the other; mutual.

   reciprocal respect.

2. given, performed, felt, etc., in return.

   reciprocal aid.

3. matching; corresponding; equivalent.

   reciprocal privileges at other health clubs.

4. Grammar. (of a pronoun or verb) expressing mutual relationship or action.

   “Each other” and “one another” are reciprocal pronouns.

5. inversely corresponding; opposing.

   reciprocal muscles in your back.

6. Mathematics. noting expressions, relations, etc., involving reciprocals.

   a reciprocal function.

7. Navigation. bearing in a direction 180° to a given direction; back.

---

noun

reciprocals plural

1. something that is reciprocal to something else.

   Faith and fear are reciprocals.

2. Also called multiplicative inverse.  Mathematics. the ratio of unity to a given quantity or expression; that by which the given quantity or expression is multiplied to produce unity.

   The reciprocal of x is 1/x.

reciprocal British  

/ rɪˈsɪprəkəl /

adjective

1. of, relating to, or designating something given by each of two people, countries, etc, to the other; mutual

   reciprocal friendship

   reciprocal trade

2. given or done in return

   a reciprocal favour

3. (of a pronoun) indicating that action is given and received by each subject; for example, each other in the sentence they started to shout at each other

4. maths of or relating to a number or quantity divided into one

5. nautical denoting a course or bearing that is 180° from the previous or assumed one

---

noun

1. something that is reciprocal

2. Also called: inverse.  maths a number or quantity that when multiplied by a given number or quantity gives a product of one

   the reciprocal of 2 is 0.5

reciprocal Scientific  

/ rĭ-sĭp′rə-kəl /

1. Either of a pair of numbers whose product is 1. For example, the number 3 is the reciprocal of 1/3.

---

reciprocal Cultural  

1. The number by which a given number must be multiplied to get a result of one. The reciprocal of one-half, for example, is two.

---

Usage

What does reciprocal mean? Reciprocal is an adjective used to describe things that involve an action done in response to another action in a way that is equivalent to it. To perform such an action is to reciprocate, and the act of doing so is called reciprocation. For example, when someone does you a favor, you can reciprocate by doing something nice for them. The word reciprocal is typically used to describe actions, relationships, or other things that involve such actions. Synonyms include mutual, equivalent, corresponding, matching, and complementary. Reciprocal can also be used as a noun. It can be used in a general way to mean something that is equivalent to something else—similar to the term counterpart. In mathematics, it’s used as a noun in a more specific way to refer to the number by which another number must be multiplied to get a result of one. For example, the reciprocal of ½ is 2 (which, in the form of a fraction, is 2/1). In math, a reciprocal is also called an inverse. Relatedly, reciprocal can also be used as an adjective to mean opposite or inversely related (which is just about the opposite of what reciprocal is generally used to mean). Example: The two museums offer a reciprocal membership, which means it gives you visiting privileges at both.

Synonym Usage

See mutual.

Other Word Forms

Derived Forms

• reciprocality
  noun
• reciprocalness
  noun
• nonreciprocal
  adjective
• unreciprocal
  adjective
• reciprocally
  adverb

Inflected Forms

Nouns

• reciprocals
  plural

Etymology

Origin of reciprocal

First recorded in 1560–70; from Latin reciproc(us) “returning, reciprocal” + -al ¹

Explanation

Reciprocal describes something that's the same on both sides. If you and your sister are in a big fight on a long car trip, you might resolve it through a reciprocal agreement that you'll stop poking her and she'll stop reading road signs out loud. The word mutual is a near synonym in most uses: reciprocal/mutual friendship, describing, a relationship in which two people feel the same way about each other, or do or give similar things to each other. If you tell someone you like them and they say, "The feelings are reciprocal," that means they like you too. In math, a reciprocal is a number that when multiplied by a given number gives one as a product.

Example Sentences

See Examples For:

reciprocal reciprocals

If exchange ceases to be reciprocal, the entire relationship changes.

From Science Daily ● Jul. 7, 2026

We need to insist on trade that is fair, reciprocal and consistent with our national interest.

From The Wall Street Journal ● Jun. 23, 2026

No money or guest points were exchanged, as it was reciprocal.

From MarketWatch ● Jun. 22, 2026

This led to a change in the rules, with the two competitions inserting reciprocal clauses in their regulations.

From BBC ● Jun. 17, 2026

A reciprocal relationship between people and clergy is dramatized as the congregation takes an active role in the recitation of the mass.

From "Hunger of Memory" by Richard Rodriguez

So, if and are negative reciprocals of one another, they can be multiplied together to yield –1.

From Textbooks ● Dec. 1, 2021

We can use the fact that perpendicular lines have slopes that are negative reciprocals.

From Textbooks ● Apr. 22, 2020

Since they are not negative reciprocals, the lines are not perpendicular.

From Textbooks ● Apr. 22, 2020

The secant, cotangent, and cosecant are all reciprocals of other functions.

From Textbooks ● Feb. 13, 2015

Barlow's Tables of squares, cubes, square roots, cube roots, reciprocals of all numbers up to 10,000.

From A System of Easy Lettering by Cromwell, John Howard

Related Words

• complementary
• mutual