• The symbol “#”, also known as hash, octothorpe, or (in North American usage) pound sign. The symbol has historically been used for a wide range of purposes, including the designation of an ordinal number and as a ligatured abbreviation for “pounds avoirdupois,” having been derived from the now rare “℔”. Since 2007, widespread usage of the symbol to introduce metadata tags on social media platforms has led to such tags being known as hashtags, and from that, the symbol itself is sometimes called a hashtag. ← Wikipedia

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