This is what I grew up alternately calling a number sign or a pound sign (lbs. not £) and not the post-internet metadata signifier hashtag from social media fame (infamy?). But then, I also grew up alternating between firefly and lightning bug for individuals of Lampyridae I was exposed to. Never met a glowworm, though.
Anyway, there are a variety of ways of expressing Unicode U+00023; three of which are:
- HEX CODE - #
- HTML CODE - #
- HTML ENTITY - #
Whereas E2 staff prefer #, my preference is choice #1, of course, because 23. Is any other reason needed? Also, am mildly surprised I've never heard anyone refer to it as a 3×3 open grid. Hmmm.
Note: # (U+00023), #, is not the same as ⋕ (U+022D5), ⋕, or ♯ (U+0266F), ♯.
Thought I was going to forget CSS code, \0023, didn't you?