Delocalised

For people who check facts

In chemical compounds, delocalised electrons that do not belong strictly to a covanlent bond or single atom, but moves more freely between the parts of the compound. This stablizes the structure.

Benzene, with delocalised electrons marked with a circle

One particular example is the benzene ring, where the central ring of carbon atoms leaves three electrons delocalised. This is presented either by drawing oscillating double bonds, or simply marking a circle in the benzene ring.

See:

benzene
metallic bond