|‘lb’ as an abbreviation for libra, or ‘pound in weight’. On the left, a handwritten ‘lb’ from the pen of Isaac Newton, and on the right, a printed ‘lb’ crossed by a bar denoting its status as an abbreviation.|
via Shady Characters: The secret life of punctuation
“The ‘#’ symbol is something of a problem child. It seems at first to be quite innocuous, a jack-of-all-trades whose names and uses correspond in a pleasingly systematic manner: ‘#5’ is read ‘number five’, leading to the name ‘number sign’; in North America, ‘5#’ means ‘five pounds in weight’, giving ‘pound sign’, while the cross-hatching suggested by its shape leads to the commonly used British name of ‘hash sign’. Dig a little deeper, though, and this glyph reveals itself to be a frustratingly multifaceted beast…”
Read the rest here.