Benzenes with more than one substituent

For disubsituted benzenes:
There are three possible relative positions for two substituents on a benzene ring. The relative positions can be indicated by numbers; however, they are commonly designated by the prefixes ortho (o-), meta (m-) or para (p-). The relationship between the two systems is seen in the examples below for any substituents G.

ortho (o-) 1,2-	meta (m-) 1,3-	para (p-) 1,4-

For trisubstituted benzenes:
The relative positions of the substituents are identified by the number of the carbon atom to which they are attached.