**Core Concept**
A "suppositious child" refers to a stillborn infant or a child born dead, often used interchangeably with the term "maccerated fetus." This term is essential in obstetrics to distinguish between a stillborn child and a live-born infant who died after birth.

**Why the Correct Answer is Right**
The term "suppositious child" is derived from the Latin word "suppositus," meaning "placed in." In the context of obstetrics, it describes a child that was never alive, as opposed to a live-born infant who died after birth. This distinction is crucial for various medical, legal, and social purposes. The suppositious child is often associated with a macerated fetus, which has undergone autolysis due to a prolonged intrauterine death.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately describe the term "suppositious child." The term is not related to the weight or size of a stillborn infant.

**Option B:** This option is incorrect as it does not provide a clear definition of the term "suppositious child." The term is not simply a synonym for "stillborn infant."

**Option C:** This option is incorrect as it does not accurately describe the etymology of the term "suppositious child." The term does not come from the Latin word "suppositus" in the context of "placing in" a womb.

**Option D:** This option is incorrect as it does not provide a clear definition of the term "suppositious child." The term is not simply a synonym for "macerated fetus."

**Clinical Pearl / High-Yield Fact**
In medical and legal contexts, it is essential to distinguish between a stillborn infant and a live-born infant who died after birth. This distinction can have significant implications for insurance, inheritance, and other social and legal matters.

**Correct Answer: B.**