What does stigma mean? It is an imputation attaching to character, moral spot or stand or brand. Stigmatize is to cast an imputation. In simple term, it is a label usually negative given to a person.
The word "stigma" is often associated with discrimination, negative feelings and attitudes. Stigma is something negative in your mind but when acted on that something either verbally or physically then that is discrimination.
For instance, when you learned that a person is HIV positive more often than not if you're not educated with the right information on HIV & AIDS and it's mode of transmission probably you would think that this person is promiscuous or a prostitute; that is stigma. When you said something bad towards the person fueled by that thought or you simply avoid him or isolated him then that is discrimination.
There are two types of stigma, the self stigma and societal stigma or stigma by association. I will discuss it on my next post.
Source: "Channels of Hope" workshop manual.