When "short" is used as an adverb, its meanings are as follows: 1. If you go short of or run short of sth, you do not have enough of it. 2. not as far as you need or expect 3. before the time expected or arranged; before the natural time.

Hi.. It basically means when there's not enough of something. For example, 'Run short' 'I ran short of tickets to sell' 'The King's reign of the country was short-lived' (the reign was a short duration) And if you mean 'shortly' then it means 'soon' 'I'll be with you shortly'