The term "niece by marriage" can be a bit of a mouthful and not everyone may be familiar with it. Luckily, there are synonyms that can easily be used in its place. One option is "niece-in-law," which is commonly used to refer to a niece who is related through marriage. Another alternative is "step-niece," which is used when the niece is related through a step-parent's marriage. Additionally, "sister-in-love" and "aunt-in-love" can be used to refer to a niece by marriage, particularly in cultures where extended family relationships are valued and celebrated. These synonyms for "niece by marriage" provide convenient and more widely recognized options for referring to family members related through marriage.