Computer Dictionary was published in 1984 by Scholastic Book Services (remember that beloved company that littered our grade school home rooms with tissue-y paper flyers full of cheaply produced paperbacks?). It retailed for $4.95, and does indeed seem to have been marketed to children (a claim I'm solely basing on the reference to "your teacher" on the first page). The premise of Computer Dictionary seems to be that contemporary dictionaries didn't included much of the new lingo attached to computing:
"[...] terms you've never heard before keep popping up every few seconds. Pixel, LOGO, semiconductor. Some aren't even words! CP/M, DOS, PL1: It's like alphabet soup."
The pages that follow are a bit more like an encyclopedia than a dictionary. Rather than providing just definitions, the book attempts to explain terms through examples geared to a middle-school reading level (making some of these definitions really confusing!). What I appreciate historically is this snapshot of an effort the make computers approachable to a lay audience. These sort of documents also provide valuable access to know what kind of words and concepts were in the popular discourse of computing during the early 1980s.
Particularly exciting/hilarious are the illustrations paired with these terms. Great effort is made to anthropomorphize the computer through whatever means possible. The computers are frequently drawn with arms, legs and faces, and interact (talk, run, play) with humans and other machines. This, of course, is a common trope for representing objects to children: asking the child to relate to an object as an active, affective being rather than inert matter (of course this being is always the human being, rather than the object's being on its own terms).
Computer Dictionary was authored by Patricia Conniffe. A less-than-rigorous Google search pulls up a little spat of these books that she authored or co-authored during the same time period, including "Word Processing", "Family Computing Dictionary of Computer Terms Made Simple", published in conjunction with Family Computing magazine, and "Activity Book for the Bank Street Writer". I'm curious to do some digging to see how similar the Family Computing Dictionary was to Computer Dictionary, since Family Computing magazine was also published by Scholastic. Family Computing magazine is a fascinating object in its own right (and one which will be getting plenty of dissertation attention, have no fear!), especially since its title transitioned several times, from Family Computing to "Family and Home Office Computing" to "Home Office Computing."
Wikipedia has also pointed me to THIS amazing historical object, a clip from the Family Computing TV show spin-off that aired on Lifetime!