complexity

noun

com·​plex·​i·​ty kəm-ˈplek-sə-tē 

käm-

plural complexities

1

: something complex

the complexities of the murder trial

2

: the quality or state of being complex

the complexity of the contract

Synonyms of complexity

• complexness
• sophistication
• intricacy
• elaborateness

Examples of complexity in a Sentence

He was impressed by the complexity of the music.

The diagram illustrates the complexity of the cell's structure.

He doesn't grasp the complexity of the situation.

Recent Examples on the Web

Europe operates three other high-performance research reactors with similar core complexities. — Aman Tripathi, Interesting Engineering, 24 Sep. 2026

Look, for example, at how even today’s AI has repeatedly solved mathematical problems within weeks or months — problems whose complexity had been foiling human mathematicians for decades or longer. — Keith Tidman, Baltimore Sun, 24 Sep. 2026

Without authentic longing, and without any bittersweet complexity to the portrait of one social order replacing another, we’re left with little more than puffs of amusement, enough to escalate your mood but bound to fade by morning. — Emily Nussbaum, New Yorker, 24 Sep. 2026

That said, Jones offered a word of warning about the complexity required for these projects. — Eben Novy-Williams, Sportico.com, 24 Sep. 2026

Word History

Etymology

complex entry 2 + -ity, perhaps after French complexité

First Known Use

1661, in the meaning defined at sense 1

Rhymes for complexity

• convexity
• perplexity

Kids Definition

complexity

noun

com·​plex·​i·​ty kəm-ˈplek-sət-ē 

käm-

plural complexities

1

: something complex

the complexities of the English language

2

: the quality or state of being complex