Semantic processing is a kind of processing which occurs after we hear a word and encode its meaning.
Semantic processing causes us to relate the word we just heard to other words with similar meanings. Once a word is perceived, it is placed in a context mentally that allows for a deeper processing. It is the deepest level of processing and it requires the listener to think about the meaning of the cue.
This semantic processing produces memory traces that last longer than those produced by shallow processing. Deep processing and semantic processing is used to creates a much stronger memory trace.