Something opposite or contrary to something else.
An opponent.
A person or thing that is entirely different from or the reverse of someone or something else; used to show contrast between two people or two things.
An antonym.
An additive inverse.
Facing, or across from.
In a complementary role to.
On another channel at the same time.
In an opposite position.
Facing in the other direction.
Of leaves and flowers, positioned directly across from each other on a stem.
Located directly across from something else, or from each other.
Of either of two complementary or mutually exclusive things.
Extremely different; inconsistent; contrary; repugnant; antagonistic.
An alternative (often shorter) name defined for an object in a database.
Any name for a taxon, usually a validly published, formally accepted one, but often also an unpublished name.
A word whose meaning is the same as that of another word.
A word or phrase with a meaning that is the same as, or very similar to, another word or phrase.
Any of the formal names for a taxon, including the valid name (i.e. the senior synonym).