The general prohibition sign, also known informally as the no symbol, ' do not' sign, circle-backslash symbol, nay, interdictory circle, prohibited symbol, don't do it symbol, or universal no, is a red circle with a 45-degree diagonal line inside the circle from upper-left to lower-right.

These signs send a clear message to all who see them that some actions are either not safe or are outright not permitted. Prohibition signs are a crucial component to maintaining safe practice and order in the workplace, whilst also helping to adhere to health, safety, and sign regulations. What type of Prohibition Sign (s) are you looking for?

The "prohibition" symbol is used on traffic signs, so that drivers can interpret traffic laws quickly while driving. For example: The symbol's use is not limited to informing drivers of motorized vehicles, and is commonly used for other forms of traffic: The symbol is used for non-traffic purposes to warn or prohibit certain activities:

For example: Some companies use the "prohibition sign" when describing the services they offer, e.g. an insect deterrent spray brand symbol showing the "prohibition sign" over a mosquito. The Ghostbusters logo is a fictional example of this, although it uses a mirror image of the symbol with the slash going from upper right down to lower left.