Promote is a term used in different contexts by the various social networks, but it always indicates some form of payment to gain access to a wider audience than could be achieved through organic content.
Facebook uses the term “boost” for promoting a specific post, but “promote” to describe promoting a Page. Twitter offers promoted Tweets, promoted accounts, and promoted trends. There’s also Promote Mode, an automated ad program on Twitter.
Learn more: How to Use Twitter Ads Like a Pro and Get the Most Out of Your Budget