Use the adjective abstract for something that is not a material object or is general and not based on specific examples.
Abstract is from a Latin word meaning “pulled away, detached,” and the basic idea is of something detached from physical, or concrete, reality. It is frequently used of ideas, meaning that they don’t have a clear applicability to real life, and of art, meaning that it doesn’t pictorially represent reality. It is also used as a noun, especially in the phrase “in the abstract” (a joke has a person laying down a new sidewalk saying “I like little boys in the abstract, but not in the concrete”), and as a verb (accented on the second syllable), meaning “to remove.”
An abstraction is a general concept or idea, rather than something concrete or tangible. In computer science, abstraction has a similar definition. It is a simplified version of something technical, such as a function or an object in a program. The goal of “abstracting” data is to reduce complexity by removing unnecessary information.
At some level, we all think of computers in abstract terms. When we type a document in a word processor, we don’t think of the CPU processing each letter we type and the data being saved to memory. When we view a webpage, we don’t think of the binary data being transferred over the Internet and being processed and rendered by the web browser. We simply type our documents and browse the web. This is how we naturally abstract computing concepts.