In English one word substitutions, which term is used for the act of killing one own sister?

Introduction / Context:
This question tests your knowledge of specific words ending in cide, which refer to the killing of a particular person or category of person. Knowing the exact term for the act of killing one own sister is useful in law, criminology, and advanced vocabulary. The options include several related words that look similar but refer to different relationships.

Given Data / Assumptions:

• The definition given is: killing one own sister.
• Option A: Regicide.
• Option B: Fratricide.
• Option C: Matricide.
• Option D: Sororicide.
• We assume the standard meanings derived from Latin roots.

Concept / Approach:
The suffix cide comes from Latin and means killing. The prefix tells you who is being killed. Frater corresponds to brother, mater to mother, soror to sister, and rex to king. Therefore, sororicide is the killing of a sister. Regicide refers to killing a king, fratricide to killing a brother, and matricide to killing a mother. Matching the correct Latin root with sister is the key to this question.

Step-by-Step Solution:
Step 1: Note that the target relationship is sister, not brother, mother, or king.Step 2: Recall that Latin soror means sister, and cide means killing, so sororicide literally means killing of a sister.Step 3: Check regicide; this combines rex or reg meaning king with cide and refers to the killing of a king.Step 4: Check fratricide; this combines frater with cide and refers to the killing of a brother.Step 5: Check matricide; this combines mater with cide and refers to the killing of a mother. Only sororicide matches the required definition.

Verification / Alternative check:
Think of related pairs like homicide (killing of a person), suicide (killing of oneself), patricide (killing of one father), and infanticide (killing of an infant). Each word has a clear root that hints at the victim. Sororicide fits into this family with soror as the root for sister. If you remember even a small table of these roots, it becomes easy to eliminate similar looking but incorrect options.

Why Other Options Are Wrong:
Regicide does not involve any family relationship and specifically refers to the killing of a king or monarch. Fratricide refers to the killing of a brother and is sometimes used more broadly for killing a fellow soldier, but it is still linked to brotherhood, not sisterhood. Matricide refers to the killing of a mother, often used in psychology and criminal law. None of these matches the exact relationship mentioned in the stem, which is sister.

Common Pitfalls:
Exam takers sometimes confuse fratricide and sororicide because both relate to siblings. A simple memory device is that fraternal twins are brothers, which links frater and brother, while sorority in universities refers to a women organisation, which links soror and sister. Connecting these familiar modern words with the older Latin based terms will help you recall the correct one even under exam pressure.

Final Answer:
The correct one word substitution for the act of killing one own sister is Sororicide, so option D is correct.