Definition
Square unit
A square unit is the area covered by one unit-by-unit square.
What it means
To measure area in square units, cover the whole shape with equal unit squares. Do not leave gaps or overlap the squares. The number of squares needed is the area.
Remember it
Tile the inside, then count the tiles: each unit square contributes 1 square unit.
Example
A rectangle has 5 rows of 3 unit squares. It contains 5 × 3 = 15 unit squares, so its area is 15 square units.
Watch for
When the side unit has a name, use the matching area unit, such as cm². “Square units” is useful for an unnamed or abstract unit grid.
Common mix-up
Perimeter counts unit lengths around the edge; area counts square units covering the inside.
Exact meaning
A square unit is an amount of area equal to the area of a unit square: a square whose side length is 1 unit.