What Do People Mean When they Refer to Their SO?

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 Getty Images/Matt Dutile

SO is the abbreviation for significant other which could mean a spouse, life partner, or someone in a long-term, committed relationship.

In some circles, especially those discussing pansexuality or open relationships, you may come across the abbreviation OSO, which refers to "other significant other." Another term used is SSO for "secondary significant other," used in partnerships where there are primary and secondary relationships. Related abbreviations include DH for darling husband, DS for darling son, and DD for darling daughter.

History of the Term

The term "significant other" was first used in 1953 by psychiatrist Harry Stack Sullivan in his book The Interpersonal Theory of Psychiatry.

The abbreviated term "SO" comes from online chat rooms during the early 1990s. People had to shorten long words when typing messages to reduce their time online. At the time, most internet connections were made via landline, and the time spent and the amount of information shared was limited and/or paid for by the amount of data.

Significant Other in Social and Business Uses

In many social or business situations, the term "significant other" refers to someone that offers support to another person as a friend, family member, partner, or spouse. SO does not refer to gender or specifically romantic entanglements, and does not specify the nature of the relationship. For instance, many hospitals now use "significant other" in their paperwork to refer to a person who can offer support during testing, treatment, or illness. Many companies will use the term on their invitations or announcements to share that the people attending the event can bring a plus one.

In the dating world, a significant other refers to a partner, girlfriend, boyfriend, spouse, or someone with whom you share an intimate, romantic relationship. Because the term doesn't imply gender, sexuality, or relationship status, many couples adopted the phrase during the 80s and 90s to avoid offense or confusion.

Synonyms for significant other include better half, civil union, boyfriend, girlfriend, domestic partner, lover, mate, partner, and spouse.

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Scientific Uses of the Term Significant Other

In psychological terms, a significant other refers to someone who holds great importance to another and affects their well-being either positively or negatively. In sociology, a significant other refers instead to a person that affects one's sense of self in an important way. In social psychology, a significant other refers to someone that helps a child socialize and takes care of them during their formative years, such as a parent, grandparent, or instructor.


  • "I met my SO when we were still in college."
  • "Doug? Oh, he's my S.".
  • "You can bring a significant other (SO) with you into the waiting room".
  • "Before you make such a big decision, talk it over with your significant other."

Significant Other Quotations

Joaquin Phoenix
"My significant other right now is myself, which is what happens when you suffer from multiple personality disorder and self-obsession."

George Weinberg
"No man wants to feel that he's there because of his woman's biological clock or because he's filling a job opening for a husband or significant other."

Nicholas Sparks
"Romance is thinking about your significant other when you are supposed to be thinking about something else."

Nick Cannon
"I think one of the most important things in a relationship is caring for your significant other through good times and bad."

Olivia Wilde
"A good litmus test is that you should be comfortable with your significant other being present when you hang out with your friend."

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