Depends on context.

The conductor of a symphony orchestra, during rehearsal, would probably refer to that as unison doubled at the octave.

A music theory student would be chastised for calling it a chord. A chord must have three or more notes, by definition. However, it could be called an implied chord if the context justified it.

An atonal composer would refer to it as a simultaneity composed of a several pitches but only one pitch class.

A musician in a rock band trying to teach his group a song would probably not refer to it as a chord as that wouldn't really accurately tell them what to play. They would probably call it a note," e.g. a "C note."

A guitarist might call it a partial chord.

A computer programmer writing, say, an Ableton plugin, might call it a special case of a chord, and it would be reasonable for a chord generator to allow for chords composer only of a single note at various octaves.

Depends on context.

The conductor of a symphony orchestra, during rehearsal, would probably refer to that as unison doubled at the octave.

A music theory student would be chastised for calling it a chord. A chord must have three or more notes, by definition. However, it could be called an implied chord if the context justified it.

An atonal composer would refer to it as a simultaneity composed of a several pitches but only one pitch class.

A musician in a rock band trying to teach his group a song would probably not refer to it as a chord as that wouldn't really accurately tell them what to play. They would probably call it a note," e.g. a "A major chord, then E minor chord, then a C note."

A guitarist might call it a partial chord.

A computer programmer writing, say, an Ableton plugin, might call it a special case of a chord, and it would be reasonable for a chord generator to allow for chords composer only of a single note at various octaves.

Depends on context.

The conductor of a symphony orchestra, during rehearsal, would probably refer to that as unison doubled at the octave.

A music theory student would be chastised for calling it a chord. A chord must have three or more notes, by definition. However, it could be called an implied chord if the context justified it.

An atonal composer would refer to it as a simultaneity composed of a single pitch class doubled at various octaves.

A musician in a rock band trying to teach his group a song would probably not refer to it as a chord as that wouldn't really accurately tell them what to play. They would probably call it a note," e.g. a "C note."

A guitarist might call it a partial chord.

A computer programmer writing, say, an Ableton plugin, might call it a special case of a chord, and it would be reasonable for a chord generator to allow for chords composer only of a single note at various octaves.

Depends on context.

The conductor of a symphony orchestra, during rehearsal, would probably refer to that as unison doubled at the octave.

A music theory student would be chastised for calling it a chord. A chord must have three or more notes, by definition. However, it could be called an implied chord if the context justified it.

An atonal composer would refer to it as a simultaneity composed of a several pitches but only one pitch class.

A musician in a rock band trying to teach his group a song would probably not refer to it as a chord as that wouldn't really accurately tell them what to play. They would probably call it a note," e.g. a "C note."

A guitarist might call it a partial chord.

A computer programmer writing, say, an Ableton plugin, might call it a special case of a chord, and it would be reasonable for a chord generator to allow for chords composer only of a single note at various octaves.