Which term is defined as a word formed from two or more whole words?

The term that describes a word formed from two or more whole words is "compound." In linguistics, a compound word is created when two or more words are combined to create a new word with a specific meaning. Common examples include "toothbrush" (tooth + brush) and "rainbow" (rain + bow). This formation allows for the expression of complex ideas or objects in a single term.

The other options, while they may appear related, do not accurately capture the essence of this specific linguistic concept. "Complex" often refers to something that is intricate or complicated rather than a word formation technique. "Composite" typically pertains to an entity made up of various components, often used in materials science or design contexts, but not specifically in linguistics. "Combination" is a broader term that refers to the act of combining elements without implying that they form a new single word. Thus, in the context of linguistics, "compound" is the appropriate and precise term for a word created from two or more whole words.