1837, William Whewell, “Inductive Epoch of Hipparchus”, in History of the Inductive Sciences, from the Earliest to the Present Times.[…], volume I, London: John W[illiam] Parker,[…]; Cambridge, Cambridgeshire: J. and J. J. Deighton, →OCLC, book III (History of Greek Astronomy), section 2 (Estimate of the Value of the Theory of Eccentrics and Epicycles), page 183:
If, when the actual motions of the heavens are calculated in the best possible way, the process is complex and difficult, and if we are discontented at this, nature, and not the astronomer, must be the object of our displeasure.
The south polar region of Promethei Planum developed a Bermuda Triangle reputation. Satellites detected intermittent mass concentrations and magnetic field shifts. In 2148, prospectors working near Deseado Crater discovered an underground complex: a Prothean observation post. The odd phenomena were generated by the operation and discharge of a mass effect core, struggling to function despite fifty millennia of neglect.
2021 February 6, The Courier-Mail, Brisbane, page 4, column 1:
A man at the complex said he had seen the often heavily made-up girls coming and going in luxury vehicles.
An assemblage of related things; a collection.
1692–1717, Robert South, Twelve Sermons Preached upon Several Occasions, 6th edition, volumes (please specify |volume=I to VI), London: […] J[ames] Bettenham, for Jonah Bowyer,[…], published 1727, →OCLC:
This parable of the wedding supper comprehends in it the whole complex of all the blessings and privileges exhibited by the gospel.
A cluster of wildfires burning in the same vicinity.
The fire complex began as two separate fires.
2020 September 16, “Millions of acres burn in California as weather improves in Northwest.”, in The New York Times, retrieved September 16, 2020:
As of early Wednesday, there were at least 25 major wildfires and fire complexes, the term given to multiple fires in a single geographic area, burning in California, Christine McMorrow, a Cal Fire information officer, said.
(taxonomy) A group of closely related species, often distinguished only with difficulty by traditional morphological methods.
2015 November 26, Mosè Manni et al., “Relevant genetic differentiation among Brazilian populations of Anastrepha fraterculus (Diptera, Tephritidae)”, in ZooKeys, volume 540, →DOI:
Since then, a good deal of research has documented and concluded that the nominal species A. fraterculus actually comprises an unresolved complex of cryptic species.
Jim has a real complex about working for a woman boss.
(chemistry) A structure consisting of a central atom or molecule weakly connected to surrounding atoms or molecules, as for example coordination complexes in inorganic chemistry and protein complexes in biochemistry.
Oxygen levels on Earth skyrocketed 2.4 billion years ago, when cyanobacteria evolved photosynthesis:[…]. The evolutionary precursor of photosynthesis is still under debate, and a new study sheds light. The critical component of the photosynthetic system is the “water-oxidizing complex”, made up of manganese atoms and a calcium atom.