What do the dots on the tempo's equal sign mean in this picture?
Music: Practice & Theory Stack Exchange is a question and answer site for musicians, students, and enthusiasts. It only takes a minute to sign up.Sign up to join this community
This means "approximately equal to". I found this with a quick Google search. Here is an example of a webpage confirming the meaning of this symbol. I must confess, I prefer to use "c.", the abbreviation for circa, in metronome markings. Here's an example:
I've also seen the "wiggly" equal sign used in metronome marks. It's the top one at this webpage (which shows quite a few different symbols for "approximately equal to").
I must confess I hadn't seen the marking in your question, though, so I've learnt something today...