reciprocal

Latin reciprocus, possibly from a phrase such as reque proque (“back and forth, to and fro”), from re- (“back”), prō (“forwards”) and -que (“and”).

• IPA^(key): /ɹɪˈsɪpɹək(ə)l/

• Audio (US)

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reciprocal (not comparable)

1. Of a feeling, action or such: mutual, uniformly felt or done by each party towards the other or others; two-way.

   reciprocal love; reciprocal duties

   • Shakespeare

     Let our reciprocal vows be remembered.

2. Mutually interchangeable.
   • I. Watts

     These two rules will render a definition reciprocal with the thing defined.

3. (grammar) expressing mutual action, applied to pronouns and verbs; also in a broad sense: reflexive
4. (mathematics) Used to denote different kinds of mutual relation; often with reference to the substitution of reciprocals for given quantities.
5. Done, given, felt, or owed in return

   a reciprocal invitation to lunch

• mutual, two-way
• contrary, opposite, converse, inverse, inverted, cross
• (grammar): reflexive
• See also Thesaurus:contrary

• irreciprocal

• reciprocity

reciprocal (plural reciprocals)

1. (arithmetic) The number obtained by dividing 1 by another given number; the result of exchanging the numerator and the denominator of a fraction.

   0.5 is the reciprocal of 2.

2. (grammar) A construction expressing mutual action.
   • 2008, Ekkehard König, ‎Volker Gast, Reciprocals and Reflexives: Theoretical and Typological Explorations

     Depending on where reciprocalization applies (syntax vs. lexicon), the relevant reciprocal verbs are claimed to exhibit specific properties, in particular: (i) syntactic reciprocals are fully productive whereas lexical reciprocals have only limited productivity; […]

• (in arithmetic): multiplicative inverse