uncle-in-law (plural uncles-in-law)
- (nonstandard) The husband of one's aunt.
1871, William Lindsay, Inquiry into the Christian law, as to the relationships which bar marriage, page 86:
- Between uncle and aunt-in-law, or uncle's wife, you have a connection of affinity, and you have the same between aunt and uncle-in-law, or aunt's wife. [sic]
- (nonstandard) The uncle of one's spouse.
Both meanings commonly used for uncle-in-law are used to define a distinction between someone who is an uncle by marriage (i.e., an in-law) and someone who is an uncle by blood (i.e., a brother of one of your parents). However both meanings are included within the standard definition of uncle, and for those who use this term, and a user may be trying to convey only one or both of the meanings given here. In general, unless there is a need for specificity, the use of uncle is to be preferred.