significant other

American  

noun

1. Sociology. a person, as a parent or peer, who has great influence on one's behavior and self-esteem.

2. a spouse or cohabiting lover. SO, S.O.

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significant other British  

noun

1. informal a spouse or lover

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Compare meaning

How does significant-other compare to similar and commonly confused words? Explore the most common comparisons:

• significant other vs. girlfriend

Example Sentences

Participants also answered questions about how satisfied they felt with their spouse or significant other, how much conflict they experienced in communication, and how confident they were that their relationship would last.

From Science Daily • Feb. 14, 2026

Spouses typically have to wait until their significant other collects retirement benefits in order to claim spousal benefits, but that is not the case for ex-spouses.

From MarketWatch • Dec. 19, 2025

The FBI thought the lead was promising enough to launch an undercover investigation, people familiar with it said, with a covert agent befriending the woman’s significant other to elicit new clues.

From The Wall Street Journal • Dec. 14, 2025

But when it comes to extended relationships we’ve got: lover, domestic partner, significant other, longtime companion.

From Los Angeles Times • Oct. 17, 2025

For instance, students were told they’ve received a text from their significant other.

From "A Deadly Wandering: A Mystery, a Landmark Investigation, and the Astonishing Science of Attention in the Digital Age" by Matt Richtel