If you mean formatting the text so that it aligns with both the left and right margin settings - it's called 'justification'.
centered
formatted
When the body is lying face up, horizontally on one's back, this is called the supine position
Stems which grow horizontally are called stolons. Stems which grow horizontally are called stolons.
This is called the lateral decuitus position. It is used mostly to look for free gas within the abdomen.
convergent
An image shot horizontally is called a landscape photograph.
Flat
One lap
This position is called short stop.
A transformation that slides a figure horizontally is called a translation. A transformation that slides a figure vertically is also called a translation.
Two triangles
wind
The cells that go across the spreadsheet horizontally is called a row of cells.