Bass versus Base

What is the Difference Between Bass and Base?

When to Use Bass

Bass can be a noun or an adjective.

As an adjective, bass describes the lower registers of sound or music.

As a noun, it can describe an instrument designed to play notes at low frequencies, a person who sings low notes in a choir, or, separately, a fish.


When to Use Base

Base can also be a noun or an adjective.

As a noun, base has several senses, including the foundation of something, either figuratively or literally, a main facility, or a term in mathematics.

As an adjective, base can mean lowly or basic, or it describes the foundation of something.

Summary

Is it bass or base? Bass and base can both be nouns or adjectives, and both have several meanings.

Generally speaking,

Use bass for musical contexts

Use base for all other contexts (except fish).
Since bass is part of the word contrabass, this should be an easy rule to remember.