I'll keep mentioning it until it sticks.
The term Sprite came from Texas Instruments.
The TMS 9918 Video-Display Processor (VDP) design was circa 1977, when Karl Guttag finished his MS degree and started working there.
In this 1980 paper, where TI was still struggling to market the TMS99x8 series, he uses the term Sprite and "Dynamic Object Oriented Character" interchangeably. (Which is why I feel Nintendo ends up using terms like "Objects").
http://www.smspower.org/Development/TMS ... osiumDraftI don't have a reference for who definitively came up with Sprite, as it gets credited to "some marketing guy at TI". I think Sprite was considered one of the hot marketing terms in the mid-to-late 70's, much like Vista was in the mid-to-late 2000's.