Refers to a relatively small raised area of land, smaller and less imposing than a 山 in the ordinary sense.
A small pile of fallen leaves formed in the yard.
There is a small hill in the middle of the park.
The children ran up the knoll.
The children played by building a little mound of sand.
The documents piled up into a small mound.
山 is the neutral word for a mountain or hill of any size, whereas 小山 specifically marks it as small compared to a real mountain.
小山 is a small hill or hillock, the direct opposite in scale to the grand, towering 大山.
Japanese noctule
Standard kanji spelling for a small hill or knoll.
A transparent compound of 小, meaning 'small,' and 山, meaning 'mountain' or 'hill'; literally, a small mountain or hill.