What is the antonym for spectrum?

There isn't a single perfect antonym for "spectrum" because the word has multiple meanings. Here are some options depending on the context:

If "spectrum" refers to a range of colors:

* Monotone: This refers to a single color or shade.

* Single color: This is a more direct way to say "not a range of colors."

If "spectrum" refers to a range of opinions or possibilities:

* Polarization: This refers to a division into two opposing sides, the opposite of a broad range of viewpoints.

* Unity: This refers to complete agreement or a lack of diversity, the opposite of a range of possibilities.

* Singularity: This refers to a single point or idea, the opposite of a spectrum of ideas.

If "spectrum" refers to a range of frequencies:

* Discrete frequency: This refers to a single, specific frequency, the opposite of a range of frequencies.

The best antonym for "spectrum" will depend on the specific context in which it is used.