What is the meaning of "others" in this sentence?

I came across a sentence on a Wikipedia article, where "others" seems to have been used as a noun. Oxford Advanced Learner's Dictionary says it can either be noun or pronoun. The sentence in question is as follows:

Somatization disorder also causes challenge and burden on the life of the caregivers or significant others of the patient.

What does "others" refer to in the statement above? Could it be a typo or does it refer to relatives and close family members of the patient?

I'd like to highlight a slightly larger chunk in your sentence:

Somatization disorder also causes challenge and burden on the life of the caregivers or significant others of the patient.

"Significant other" is a strong collocation; together, these words take on meaning beyond the two words separately. As explained on Wikipedia:

Significant other (abbreviated SO) is colloquially used as a gender-neutral term for a person's partner in an intimate relationship without disclosing or presuming anything about marital status, relationship status, or sexual orientation.

Without recognizing the full collocation, then "others" would indeed appear rather confusing.