Looking for a term, phrase or idiom that best describes a special type of relationship between two parties, not necessarily humans, in which both gain unprecedented benefits. However, such advantages could not be acquired without the relationship; they can continue their own ways without that. In fact, the relationship will add something invaluable.

The desired word should complete such a sentence : There is a ---- relationship between concept A and B.

  • 22
    Mutualy beneficial. --- but 'unprecedented benefits'? Unprecedented for A and B, or globally?
    – loonquawl
    Commented Sep 3, 2018 at 14:34
  • @loonquawl, For A and B, of course!
    – Eilia
    Commented Sep 3, 2018 at 14:45
  • 5
    There's no English word that combines the meanings of "mutually beneficial" and "without precedent". You're getting answers for the first meaning alone.
    – trent
    Commented Sep 4, 2018 at 12:44
  • 1
    Here's more of an opinion than an authoritative answer for you: I might refer to this as a resonant relationship. When a sound is produced at an appropriate frequency, it can cause a nearby material to vibrate and produce secondary sound where before there was none. The material is said to resonate with or be resonant with the sound and even the sound's source. Usually resonate as an idiom means agree with but resonant is different enough to bear the meaning you describe without confusion.
    – talrnu
    Commented Sep 4, 2018 at 22:15
  • 1
    I wouldn't consider this an answer, but "non-zero-sum-game" comes to mind
    – JacobIRR
    Commented Sep 5, 2018 at 23:31

7 Answers 7


There is a relationship of synergy/ (synergistic relationship) between concept A and concept B working together.

A synergistic relationship is one where two parties, or things, working together, are able to produce a result that is greater than the sum of what they can each do individually.

It is perhaps OED sense 3 of synergy which seems relevant here:

  1. Any interaction or cooperation which is mutually reinforcing; a dynamic, productive, or profitable affinity, association, or link.

1957 R. B. Cattell Personality & Motivation xvii. 791 Immediate synergy through group membership..expresses the energy going into the group life as a result of satisfaction with fellow members.

1981 Economist 28 Nov. 19/2 Others, through mergers (eg, research houses into retail brokerage houses), have demonstrated that there is something to be said for synergy.

1990 B. Burrough & J. Helyar Barbarians at Gate xvi. 436 They had nothing in common. No synergy. No flow of ideas or people back and forth.

2006 Wall St. Jrnl. 27 Nov. r4/1 A software and hardware ‘ecosystem’ that tries to mimic the successful synergy between iTunes software and iPod gadgets


  • 8
    I like synergistic better than symbiotic, because it's more "literal" (and OP mentions the possibility of using the term in relation to concepts, where metaphoric symbiotic isn't necessarily appropriate). Commented Sep 3, 2018 at 15:04
  • 3
    I think this is a better word too, I wish I'd thought of it in time. :-)
    – Hellion
    Commented Sep 3, 2018 at 16:36
  • 7
    remember in the UK at least synergy used in this sense is considered "management bollocks" amazon.co.uk/Little-Book-Management-Bollocks/dp/0743404130
    – WendyG
    Commented Sep 3, 2018 at 16:58
  • I'm not a fan of this one TBH; a synergistic relationship is defined by the output of the collaboration of the involved parties, and does not necessarily require or imply a direct benefit to any of them.
    – Doktor J
    Commented Sep 4, 2018 at 16:30
  • @DoktorJ - At least it does not imply (symbiotic) "that the two parties are incapable of functioning alone and separation would be disastrous." Also, "mutually reinforcing" implicitly implies benefits to all parties involved, directly or otherwise.
    – Mazura
    Commented Sep 5, 2018 at 0:18

A symbiotic relationship is one where each party provides benefits to the other that they cannot get on their own:

b : characterized by or being a close, cooperative, or interdependent relationship
Sigal's study … illustrates how reporters' constant need for news and how government officials' need for publicity and favorable coverage for their agencies combine into a symbiotic relationship between Washington reporters and officials. —Charles R. Wright
definition from m-w.com

  • 19
    But note that this common usage is technically incorrect, from the point of view of the specialist usage in biology from which it benefits. Symbiotic simply means two organisms living together, the term mutualistic is used for a mutually beneficial relationship. Commented Sep 3, 2018 at 15:09
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    @JackAidley Yeah I felt like mentioning that. In biology there are different types of symbiosis, commensal, mutual, and parasitic. Outside biology in general use it's fine. In fact even some dictionaries define symbiosis in the specific biology sense to be "typically to the advantage of both"
    – Zebrafish
    Commented Sep 3, 2018 at 21:35
  • 4
    "Symbiotic" implies that the two parties are incapable of functioning alone and separation would be disastrous. As in your example.
    – Agent_L
    Commented Sep 4, 2018 at 12:33
  • 1
    Outside biology I'd venture to say "mutually beneficial" is preferable to "symbiotic", which certainly emphasizes the interdependence in a relationship but not an overall positive or negative connotation. So if we have to say "mutually symbiotic" in biology to have that level of specificity, I'd say the word "mutual" is pretty much essential to fully meeting OP's needs. Commented Sep 5, 2018 at 18:38
  • 2
    @only_pro I think the example of actual usage that is included in the dictionary's entry counters your claim; it is clearly referring to (sets of) humans and how they get along with each other.
    – Hellion
    Commented Sep 5, 2018 at 19:31

"Mutually beneficial" is the term used almost exclusively, particularly when talking about any kind of interpersonal, business, or diplomatic relationship/partnership. (As an aside, 'Partnership' also implies a positive outcome for all parties)

The other answers here are very accurate in a scientific or academic sense, but practically not used in any other setting.

It would be very unusual and quite jarring to see/hear them in any other kind of speech or writing (casual or formal, fiction or non-fiction).

  • 3
    This is the best in my opinion for everyday usage, while symbiotic isn't esoteric, it's more scientific English than everyday English in my opinion, and gets across the same information.
    – colsw
    Commented Sep 4, 2018 at 12:35
  • This is a better general term. Symbiotic generally refers to biology where two species have established a mutually beneficial relationship (it can be used in other scenarios, but I don't believe is widely used as such). Synergistic refers less to the benefit each individual party receives, and is more specific to the combined output of that relationship (which may not directly benefit either party).
    – Doktor J
    Commented Sep 4, 2018 at 16:27
  • 3
    mutually advantageous is a similar possibility
    – Henry
    Commented Sep 4, 2018 at 16:29
  • 1
    Every Google Ngram search I could think of indicates this is incorrect - the occurrence of most permutations of "mutually beneficial" is statistically irrelevant to equivalent permutations of "symbiotic". Where are you drawing this conclusion from?
    – talrnu
    Commented Sep 4, 2018 at 22:36
  • @talrnu you'll have to only count occurrences which refer to interpersonal and/or human relationships, as stated in this answer. Then the actual count would probably differ Commented Sep 5, 2018 at 7:49

I suggest the phrase "win-win" describes what you are looking for; see the Cambridge Dictionary definition.

A win-win situation or result is one that is good for everyone who is involved:

Flexible working hours are a win-win situation for employers and employees.

And win-win implies a relationship or trade of goods or services that benefits all parties and wouldn't exist with out the relationship.


Reading through the other answers, I will also add that win-win is more colloquial and avoids some of the issues raised by others.

  • 1
    win-win is commonly used to describe a single interaction, transaction, or deal, like your examples. But not an ongoing relationship. Commented Sep 5, 2018 at 22:34
  • @PeterCordes: True but a win-win can be a long term relationship too; for example, after WW2, Japan became one of America's greatest allies because the US didn't seek revenge; only to rebuild.
    – djm
    Commented Sep 6, 2018 at 13:21
  • @PeterCordes: And I just reread the OP and I'm sorry, but nowhere do I see "long term relationship" mentioned or implied.
    – djm
    Commented Sep 6, 2018 at 13:23
  • I didn't say "long term", I said "ongoing". I can't recall having heard it used to describe more than individual transactions, even between allied countries or human friends. An agreement between two people to cooperate in future (even in the short term) could be described as win-win, but usually not the resulting relationship. If the word "relationship" is used, the phrase is nearly always "mutually-beneficial relationship". Commented Sep 6, 2018 at 15:27


I would use reciprocal if both parties give to each other in order to receive the benefits the other provides. It has a sort of "quid pro quo" connotation.

Definition of reciprocal

  1. a : inversely related : opposite

    b : of, constituting, or resulting from paired crosses in which the kind that supplies the male parent of the first cross supplies the female parent of the second cross and vice versa

  2. shared, felt, or shown by both sides

  3. serving to reciprocate : consisting of or functioning as a return in kind; the reciprocal devastation of nuclear war

  4. mutually corresponding agreed to extend reciprocal privileges to each other's citizens

    b : marked by or based on reciprocity; reciprocal trade agreements



Positive sum

A more technical/scientific term would be positive sum from the game theory

A positive sum occurs when resources are somehow increased and the desires and needs of all concerned are satisfied


This is a positive sum relationship.


I know it's not quite fully accurate, but to communicate the essence that you're trying to convey, I'd actually use unprecedented.

There is an unprecedented relationship between concept A and B.

Whilst the nameplate value for the word is never having happened or existed in the past it carries the tones of of exceedingly high value that I think you're trying to convey.

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