A synonym is each of two or more names of the same rank used to denote the same taxonomic taxon.
A junior synonym is the youngest of the two or more names given to the same taxon.
A senior synonym is the oldest of the two or more names given to the same taxon.
In principle; the senior synonym always has precedence over the junior synonym.
A subjective synonym is each of two or more names whose synonymy is only a matter of opinion of the taxonomist.
An objective synonym is each of two or more synonyms that denote nominal taxa with the same name-bearing type.
