A sender is a person or thing that initiates or starts something, such as a message or package, with the intention of it being received by someone else. Full definition
All of this «unlocking» and «locking up» of bitcoin is done by senders of transactions, and subsequently transmitted over the Bitcoin network as packages of information. (bitcoinmagazine.com)
As of July 1st, 2014, Canada has new requirements for senders of commercial emails sent to or within Canada that differ from the U.S.... (nar.realtor)
You'll get through your emails quicker if you sort by sender instead of by date. (entrepreneur.com)