Question

This list consists of words that mean hill. How do the words differ from each other?

slope, rise, mound, knoll, mountain

Each suggests a different size.

Each suggests a different shape.

Each suggests a different location.

Each suggests a different type of land covering the hill.

Answer 1

Short answer: they overlap but are not interchangeable. The five words differ mainly in whether they name an entire landform or just an inclined part, and in typical size, shape, setting and surface cover/connotation.

Below I summarize each word along the four axes you gave, then evaluate the four general statements.

slope
- Size: not a size class — a slope can belong to anything from a small bank to a huge mountain face.
- Shape: an inclined surface (plane or curved face), not a rounded summit.
- Typical location: the side of a hill, mountain, valley, road embankment, riverbank, etc.
- Typical cover/type: any cover — grass, rock, soil, snow — the word says nothing about material.
- Note: “slope” is usually a feature (the incline) rather than a whole hill.

rise
- Size: small to modest elevation; a gentle, noticeable increase in ground level.
- Shape: gentle convex uplift rather than steep; subtle rather than sharply peaked.
- Typical location: fields, plains, roads — places where the land “rises” slightly from surroundings.
- Typical cover/type: usually turf, grass or soil; neutral term about surface.
- Note: often used when the elevation is minor or relative (a “rise in the road”).

mound
- Size: small to medium; can be natural or artificial.
- Shape: rounded, often dome-like or conical.
- Typical location: gardens, fields, archaeological sites, animal/ant/termite constructions, earthworks.
- Typical cover/type: usually earth/soil, turf, sand; often man-made or deliberately formed.
- Note: “mound” often implies an object placed or piled (e.g., burial mound).

knoll
- Size: small hill; generally smaller than a hill people would call a “hill,” definitely much smaller than a mountain.
- Shape: small, rounded, gentle summit — a little dome or hump.
- Typical location: pastoral landscapes, parkland, cemeteries; often grassy.
- Typical cover/type: usually grass or light vegetation; evokes a grassy, pleasant rise.
- Note: knoll has a quaint/poetic feel (e.g., “a lonely knoll”).

mountain
- Size: large; much higher and more massive than hills or knolls.
- Shape: steep, often rugged with a distinct summit; shapes vary (conical, ridged, massif).
- Typical location: mountain ranges, highlands.
- Typical cover/type: rock, scree, alpine vegetation, snow/ice at higher elevations.
- Note: often defined by local elevation/relief criteria; carries implication of significant height and steepness.

Evaluation of your four statements
- “Each suggests a different size.” Largely true: rise/knoll/mound imply small, mountain implies large. “Slope” is not a size category, so it doesn’t fit cleanly.
- “Each suggests a different shape.” Mostly true: slope = inclined plane, rise = gentle convex, mound/knoll = rounded dome, mountain = steep/peaked or rugged.
- “Each suggests a different location.” Partly true: some words imply likely settings (mound: field/archaeology, knoll: pasture, mountain: highland), but all can occur in varied locations.
- “Each suggests a different type of land covering the hill.” Sometimes true by connotation (knoll → grass, mound → earth/soil, mountain → rock/snow), but none strictly requires a specific cover; usage is flexible.

Bottom line: the differences are real but fuzzy — size and shape and connotation help you choose the right word, but context and regional usage matter.