Thank you to everybody who responded to my request for clarification of the above. I wrote to the Oxford Dictionary to find out why they defined uncle the way they did and suggested that they make at a distinction between a uncle by blood and an uncle by marriage as a convention. I received the following replay today - >Thank you for your message. The English language is noticeably lacking in specific terms for relationships, and we often receive enquiries from bewildered foreigners requiring equivalents for terms in their own languages, such as those which distinguish between paternal and maternal grandparents, or cousins of varying degrees. It does not appear, historically speaking, that the distinction you make has been recognized in law; I have found nothing on the subject in our large collection of legal dictionaries. The OED does mention the term UNCLE-IN-LAW as meaning 'the husband of one's aunt', but with no evidence later than 1779. As all our dictionary definitions are based on evidence of actual use, the fact that we do not normally distinguish between blood relations and relations by marriage is what influences the form of this definition.< So there you have it. Bob O.