X Mark

An X mark is a mark used to indicate the concept of negation (for example "no, this has not been verified" or "no, I don't agree") as well as an in...

Square Root

In mathematics, a square root of a number a is a number y such that y2 = a; in other words, a number y whose square (the result of multiplying the ...


In addition to being the 18th letter of the Greek alphabet, sigma also means 'sum' and 'deviation' in themathematics world.

Plus Sign

The plus sign is written as a cross of horizontal and vertical lines: + The plus sign indicates addition operation of 2 numbers or expressions.


It is approximately equal to 3.14159. It has been represented by the Greek letter "π" since the mid-18th century, though it is also sometimes spell...

Deathly Hallows

The triangular Deathly Hallows symbol is comprised of theElder Wand, the Resurrection Stone and the Cloak of Invisibility. Whoever possesses all th...

No Left Turn Sign

This traffic sign indicates that left turns are prohibited.

Harry Potter Sign of the Deathly Hallows

The Sign of the Deathly Hallows is a triangular mark used as a representation of the Deathly Hallows, three legendary objects that allegedly, if un...

Traffic Light Sign

A road signal for directing vehicular traffic by means of colored lights, typically red for stop, green for go, and yellow for proceed with caution.

No Parking Sign

This sign is used where parking is prohibited.

Fire Exit Sign

Fire Exit Signs and Emergency Exit Signs direct people to the proper exits in a fire emergency.

Fallen Rocks Sign

The Fallen Rocks sign indicates to drivers that they are approaching an area which is susceptible to falling rock or landslides, and that fallen ro...