significant other

US /sɪɡˈnɪf.ɪ.kənt ˈʌð.ər/
UK /sɪɡˈnɪf.ɪ.kənt ˈʌð.ər/
"significant other" picture
1.

大切な人, パートナー

a person with whom someone has a long-term, committed relationship, especially one who is not a spouse but is considered a partner in life

:
She introduced him to her significant other at the party.
彼女は彼をパーティーで大切な人に紹介した。
Many people prefer to use 'significant other' instead of 'boyfriend' or 'girlfriend' to be more inclusive.
多くの人は、より包括的であるために「ボーイフレンド」や「ガールフレンド」の代わりに「大切な人」を使うことを好む。