The originator is an 11 alpha-numeric string (or 16 numeric string) of characters that is sent along with each message, whose purpose is to identify who/where the message has come from.
In person-to-person (P2P) messaging, the originator is automatically set as the sender's mobile phone, so if his/her phone number is stored on the receiving phone, its inbox automatically displays the name under which it has been saved.
In business-to-person (B2P) messaging, defining the originator to reflect the name of your organisation, for example, strengthens its brand, impresses potential clients and gives reassurance to recipients that messages are official. The use of a mobile phone number, on the other hand, makes bulk messages seem more personal and, for two-way applications, makes it easy for recipients to respond.
The correct term for the originator, according to GSM standards is the "source address", but it is also known as the "sender id", "from field", "brand" and "footer".