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noun com·plex \ˈkäm-ˌpleks\

Simple Definition of complex

  • : a group of buildings, apartments, etc., that are located near each other and used for a particular purpose

  • : an emotional problem that causes someone to think or worry too much about something

  • : a group of things that are connected in complicated ways

Source: Merriam-Webster's Learner's Dictionary

Full Definition of complex

  1. 1 :  a whole made up of complicated or interrelated parts <a complex of welfare programs> <the military-industrial complex>

  2. 2 a :  a group of culture traits relating to a single activity (as hunting), process (as use of flint), or culture unit b (1) :  a group of repressed desires and memories that exerts a dominating influence upon the personality (2) :  an exaggerated reaction to or preoccupation with a subject or situation c :  a group of obviously related units of which the degree and nature of the relationship is imperfectly known d :  the sum of factors (as symptoms) characterizing a disease or condition

  3. 3 :  a chemical association of two or more species (as ions or molecules) joined usually by weak electrostatic bonds rather than covalent bonds

  4. 4 :  a building or group of buildings housing related units <an apartment complex> <a sports complex>

Examples of complex in a sentence

  1. She has a complex about her appearance.

  2. a complex of protein molecules

Origin of complex

Late Latin complexus totality, from Latin, embrace, from complecti

First Known Use: 1643

Other Chemical Engineering Terms



adjective com·plex \käm-ˈpleks, kəm-ˈ, ˈkäm-ˌ\

Simple Definition of complex

  • : having parts that connect or go together in complicated ways

  • : not easy to understand or explain : not simple

  • grammar : consisting of a main clause and one or more additional clauses

Source: Merriam-Webster's Learner's Dictionary

Full Definition of complex

  1. 1 a :  composed of two or more parts :  composite b (1) of a word :  having a bound form as one or more of its immediate constituents <unmanly is a complex word> (2) of a sentence :  consisting of a main clause and one or more subordinate clauses

  2. 2 :  hard to separate, analyze, or solve

  3. 3 :  of, concerned with, being, or containing complex numbers <a complex root> <complex analysis>

complexly adverb
complexness noun

Examples of complex in a sentence

  1. The house's wiring is complex.

  2. The situation is more complex than you realize.

Origin of complex

Latin complexus, past participle of complecti to embrace, comprise (a multitude of objects), from com- + plectere to braid — more at ply

First Known Use: 1645

Synonym Discussion of complex

complex, complicated, intricate, involved, knotty mean having confusingly interrelated parts. complex suggests the unavoidable result of a necessary combining and does not imply a fault or failure <a complex recipe>. complicated applies to what offers great difficulty in understanding, solving, or explaining <complicated legal procedures>. intricate suggests such interlacing of parts as to make it nearly impossible to follow or grasp them separately <an intricate web of deceit>. involved implies extreme complication and often disorder <a rambling, involved explanation>. knotty suggests complication and entanglement that make solution or understanding improbable <knotty ethical questions>.



verb com·plex \same as 2\

Definition of complex

  1. transitive verb
  2. 1 :  to make complex or into a complex

  3. 2 :  chelate

complexation play \ˌkäm-ˌplek-ˈsā-shən, kəm-\ noun

Examples of complex in a sentence

  1. <there's no need to complex what should be a simple process for obtaining a building permit>


First Known Use of complex


Other Chemical Engineering Terms

COMPLEX Defined for Kids


adjective com·plex \käm-ˈpleks, kəm-ˈpleks, ˈkäm-ˌpleks\

Definition of complex for Students

  1. 1 :  not easy to understand or explain :  not simple <complex instructions>

  2. 2 :  having parts that go together in complicated ways <a complex invention>

Seen and Heard

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a division or portion of a pool or whole

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