`num`

plural # · plural #s

1. USPound (unit of weight).

   3#

   three pounds

2. attributiveprecedes a numeralNumber.

   #3

   number three

   Synonyms: no.

3. InternetNumber.

   I have collected U.S. Stamps since I was a boy back in the 1950's. At that time there was a low # being printed and it was affordable.

   1997 June 17, RYankowski [username], “Why collect new U.S.?”, in rec.collecting.stamps (Usenet)

4. informalHashtag.
5. ScrabbleIn English-language Scrabble, indicates that a word is only found in the British accepted word list and not the North American list.

   PTERION#