# Proper definitions of mother-in-law and sister-in-law relationships in English and their calculation in Gramps **URL:** \ **Category:** Genealogy\ **Tags:** bug-filed\ **Created:** [November 14, 2025, 2:42pm UTC](https://gramps.discourse.group/t/proper-definitions-of-mother-in-law-and-sister-in-law-relationships-in-english-and-their-calculation-in-gramps/8810 "2025-11-14T14:42:00Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![petr\_fedorov](https://yyz2.discourse-cdn.com/free1/user_avatar/gramps.discourse.group/petr_fedorov/32/9556_2.png) [@petr\_fedorov](https://gramps.discourse.group/u/petr_fedorov)\ **Post date:** [November 14, 2025, 2:42pm UTC](https://gramps.discourse.group/t/proper-definitions-of-mother-in-law-and-sister-in-law-relationships-in-english-and-their-calculation-in-gramps/8810/1 "2025-11-14T14:42:00Z")
Hello! Since I’m not a native speaker of English I would like to confirm that my understanding of terminology for basic in-law relationships in English is correct. This is related to the bug I recently filled as described below. I found the following definitions in Merriam-Webster dictionary: ![mother-in-law-definition](https://global.discourse-cdn.com/free1/uploads/gramps/original/2X/3/3ddb8ea829ef2896e4c501963d872dd91422b67a.jpeg) and ![sister-in-law-definition](https://global.discourse-cdn.com/free1/uploads/gramps/original/2X/b/b1fb0fd32efbe485c1b253f2ba5ac49f8c5aa6b6.jpeg) Collins dictionary defines mother-in-law similarly to Merriam-Webster, but gives a restricted definition of sister-in-law (note that **2b** definition found in Merriam-Webster is not given by Collins): ![sister-in-law-definition-collins](https://global.discourse-cdn.com/free1/uploads/gramps/original/2X/e/edad20146fc247cfcb36c3bb5aeab1b6264e8407.jpeg) Now consider the family lines graph below created from Example database: ![in-law_familylines_graph](https://global.discourse-cdn.com/free1/uploads/gramps/original/2X/6/6cf5fa6f8af420e1a6399296cad74120b408610c.jpeg) If we set **Lessard, Elinor Jane** as Home Person and ask what kind of relationship exists between her and another persons (Quick View→Relation to Home Person) we get the following results: 1. **Page, Clara Belle** is ‘mother-in-law’ 2. **Klein, Alma Katherine** is ‘mother-in-law’ 3. **Черных, Mary Helen** is ‘sister-in-law’ Taking the above definitions we see that 1. is a correct relationship according to both dictionaries, 2. is a wrong relationship according to both dictionaries and, finally, 3. is correct according to Merriam-Webster and wrong according to Collins. I recently filled the bug [14309](https://gramps-project.org/bugs/view.php?id=14039) regarding 2. above with the intention to fix it. But before that I would like to receive a confirmation from Gramps community that my understanding is correct. Thanks in advance for your feedback ! ---
**Author:** ![emyoulation](https://yyz2.discourse-cdn.com/free1/user_avatar/gramps.discourse.group/emyoulation/32/67_2.png) [@emyoulation](https://gramps.discourse.group/u/emyoulation)\ **Post date:** [November 14, 2025, 3:03pm UTC](https://gramps.discourse.group/t/proper-definitions-of-mother-in-law-and-sister-in-law-relationships-in-english-and-their-calculation-in-gramps/8810/2 "2025-11-14T15:03:30Z")
So, you want the calculator to identify them as “stepmother-in-law” and “spouse of halfsister-in-law”? Although the relationship for **Klein, Alma Katherine** could be more complicated. If the father was widowed, then she is almost never be referred to as a “step”. But rather, as the “father-in-law’s late 1st wife”. And socially, it is often considered rude (or discriminatory) to point out that a relationship is anything but biological. Even though it remains genetically important. ---
**Author:** ![petr\_fedorov](https://yyz2.discourse-cdn.com/free1/user_avatar/gramps.discourse.group/petr_fedorov/32/9556_2.png) [@petr\_fedorov](https://gramps.discourse.group/u/petr_fedorov)\ **Post date:** [November 14, 2025, 4:02pm UTC](https://gramps.discourse.group/t/proper-definitions-of-mother-in-law-and-sister-in-law-relationships-in-english-and-their-calculation-in-gramps/8810/3 "2025-11-14T16:02:01Z")
> [@emyoulation](#): > > So, you want the calculator to identify them as “stepmother-in-law” and “spouse of halfsister-in-law”? It is possible and rather easy to do. I estimate implementation difficulties of the various options as follows: - **Easy** : ‘stepmother-in-law’, ‘stepsister-in-law’ - **Moderate** : ‘father-in-law’s wife’, ‘brother–in-law’s wife’ - **Difficult** : ‘father-in-law’s late 1st wife’, ‘spouse of half brother-in-law’ I would definitely implement the Easy option, if it was an acceptable one, would think about the Moderate one and would think twice whether to implement the Difficult one ---
**Author:** ![emyoulation](https://yyz2.discourse-cdn.com/free1/user_avatar/gramps.discourse.group/emyoulation/32/67_2.png) [@emyoulation](https://gramps.discourse.group/u/emyoulation)\ **Post date:** [November 14, 2025, 4:17pm UTC](https://gramps.discourse.group/t/proper-definitions-of-mother-in-law-and-sister-in-law-relationships-in-english-and-their-calculation-in-gramps/8810/4 "2025-11-14T16:17:31Z")
From the diagram, that is a half-sister, not a step-sister. Whoops… wife of a half-brother‐in-law . ---
**Author:** ![petr\_fedorov](https://yyz2.discourse-cdn.com/free1/user_avatar/gramps.discourse.group/petr_fedorov/32/9556_2.png) [@petr\_fedorov](https://gramps.discourse.group/u/petr_fedorov)\ **Post date:** [November 17, 2025, 12:07pm UTC](https://gramps.discourse.group/t/proper-definitions-of-mother-in-law-and-sister-in-law-relationships-in-english-and-their-calculation-in-gramps/8810/5 "2025-11-17T12:07:34Z")
Here is the description of the proposed changes. Please let me know what do you think. Column **Current** in the table below shows how Gramps 6.0.6. reports the relationship between Persons B and A (Quick View-\>Relation to Home Person) and column **Proposed** - how the relationship will be reported in the future. An empty field in the **Proposed** column implies that no change will be made. | Seq. | Person (A) | Person (B) | Current | Proposed | | --- | --- | --- | --- | --- | | 1. | Lessard, Elinor Jane | Warner, Michael Warren | brother-in-law | | | 2. | Lessard, Elinor Jane | Черных, Mary Helen | sister-in-law | wife of brother-in-law | | 3. | Lessard, Elinor Jane | Warner, Martin Bogarte | father-in-law | | | 4. | Lessard, Elinor Jane | Page, Clara Belle | mother-in-law | | | 5. | Lessard, Elinor Jane | Klein, Alma Katherine | mother-in-law | wife of father-in-law | I attach here the same graph as above for convenience ![in-law_familylines_graph](https://global.discourse-cdn.com/free1/uploads/gramps/original/2X/6/6cf5fa6f8af420e1a6399296cad74120b408610c.jpeg) All of the above relationships are handled by single method: `RelationshipCalculator.get_single_relationship_string()`, even rows 1. and 2. `RelationshipCalculator.get_sibling_relationship_string()` is not called for ‘in-law’ relationships at all by QuickView plugin. I would propose to leave this ‘as-is’ since many `rel_xx.py` localizations implement `get_sibling_relationship_string()` method and at the moment it is not clear whether they are prepared to handle ‘in-law’ relationships between siblings properly. This implies that we can’t currently implement that Черных, Mary Helen is the ‘wife of a half-brother‐in-law’ ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/gramps/original/1X/2ac1e712b7adf612e31ca08a55419f4cf37c0158.png) [@system](https://gramps.discourse.group/u/system)\ **Post date:** [December 17, 2025, 12:07pm UTC](https://gramps.discourse.group/t/proper-definitions-of-mother-in-law-and-sister-in-law-relationships-in-english-and-their-calculation-in-gramps/8810/6 "2025-12-17T12:07:54Z")
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