"On a similar note" meaning

Question

I've been hearing this phrase from time to time and the (free) online dictionaries that I have access to and that show up on my IP address don't have any entry for it. It's meaning may be obvious but like most phrases in English, I doubt it's that simple.

Example:

On a similar note, be sure to read Mary Pilon's post on one veteran who is encouraging today's soldiers to do the same

I think here it means "similarly" and something along the lines of this was said earlier.

Another example:

4. Attendance at sporting events might soon be allowed.
5. On a similar note, movie theatres might soon be reopening.

BC Local News

It probably means "similarly" here too, but I need a second opinion.

So what does this phrase originally mean? Does it only mean "similarly" or depending on the context, its meaning can change?

Answer 1

I think this is related to the definition of note (related to the idea of a musical note) -

a particular quality or tone that reflects or expresses a mood or attitude (Oxford Dictionaries)

You are correct in thinking that it means on a similar theme or speaking from a similar point of view.

Answer 2

Similarly is among the synonyms of on a similar note provided by Power Thesaurus.

I had thought of along the same lines or from the same perspective.

It can also mean simply in addition.

The particular note in this idiom may also refer to a written note, it seems:

It is unclear exactly how this idiom originated. Some sources speculate that it comes from a musical note. This seems to make sense. The notes of music can sound happy or sad, and they could metaphorically represent upbeat or upsetting conversations. Alternatively, it could relate to written notes or comments. A meeting might cover different bullet points or notes. If one wanted to transition from one of these notes to another, it would make sense to use this expression.

(WritingExplained)