missing link

American  

[mis-ing lingk] / ˈmɪs ɪŋ ˈlɪŋk /

noun

1. a hypothetical form of animal assumed to have constituted a connecting link between the anthropoid apes and humans, identified by some authorities as constituting the genus Australopithecus.

2. something lacking for the completion of a series or sequence.

   It’s tricky to find the missing link between children’s books and adult fiction.

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missing link British  

noun

1. (sometimes capitals) a hypothetical extinct animal or animal group, formerly thought to be intermediate between the anthropoid apes and man

2. any missing section or part in an otherwise complete series

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missing link Cultural  

1. A supposed animal midway in evolution between apes and humans. The term is based on a misunderstanding about the theory of evolution, which does not state that humans are descended from apes, but rather maintains that both humans and apes descended from a common ancestor. Modern evolutionary scientists do not search for a “missing link.”

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Etymology

Origin of missing link

First recorded in 1850–55

Example Sentences

“It’s kind of a missing link in the system, through a fairly densely populated part of the city,” Elkind said of the proposed K Line extension.

From Los Angeles Times • Mar. 24, 2026

The critical missing link at present is a viable transitional government.

From The Wall Street Journal • Mar. 17, 2026

And first-time buyers, long a missing link of the housing market, represented some 34% of February sales, one of the highest rates in five years, according to National Association of Realtors data.

From Barron's • Mar. 14, 2026

The biggest missing link from your letter is whether your husband’s pension offers 50%, 75%, or 100% survivorship.

From MarketWatch • Dec. 9, 2025

He had found the missing link in Harvey’s description of blood circulation, a link which Harvey himself had guessed must be there, but could not detect with the instruments at his disposal.

From "The Scientists" by John Gribbin