Snip

You'll have better luck searching if you use the term knee wall.

No - half wall is correct.

knee wall is under an eave supporting a roof.

Proper definition knee wall (1) A wall that shortens the span of the roof
rafters by acting as a knee brace, in that it supports the rafters at some
intermediate point along their length. (2) A short wall con-structed to
extend the height of an ex-isting foundation or other wall system