stolons
you may think i am kidding but the horizontally aligned elements are called periods. The vertical is called groups.
vertically they're called groups and horizontally periods
When air is moving horizontally, that is known as wind.
Because it won't settle out flat (horizontally) by itself. It has its own property called "angle of repose".
Stems which grow horizontally are called stolons. Stems which grow horizontally are called stolons.
level
level
level
An image shot horizontally is called a landscape photograph.
flat
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.
It is called the equator
rows