A number made by squaring a whole number.
Example: 4 × 4 = 16, so 16 is a square number.
Here are the first few square numbers:
0 (=0×0)
1 (=1×1)
4 (=2×2)
9 (=3×3)
16 (=4×4)
25 (=5×5)
36, 49, 64, 81, 100, 121, 144, ... and so on
Also known as "Perfect Square".