What term is used to refer to a person's husband or wife?

The term "spouse" specifically refers to a person's legally recognized husband or wife. In the context of family and legal documents, "spouse" denotes that there is a formal union, typically established through marriage. This is the precise and widely accepted definition, which is important when filling out applications or legal forms, as it clearly indicates the relationship status.

Other options, such as "partner," "companion," and "ally," do not carry the same legal connotation. While "partner" can sometimes be used informally to describe someone in a romantic relationship, it does not necessarily imply a legal marriage. "Companion" tends to refer to someone who accompanies or spends time with another person, typically without the legal recognition that "spouse" entails. "Ally" is used in a completely different context, often referring to a person or group that supports or cooperates with another, particularly in political or military situations, and is not applicable here. Thus, "spouse" is the most accurate and relevant term for describing a husband or wife.