Compounding
One derivational process we have already discussed is compounding. Here are some basic examples:
(3) English compounds
tool + bar
amusement + park
puppy + love
coffee + house
To give a more extreme example, if someone asks us what Violet does for a living, we might respond:
(4) She’s a high voltage electricity grid systems supervisor.
There is evidence that high voltage electricity grid systems supervisor is a single noun. First, its distribution matches that of any other noun, so we can insert it into phrases like [a good N] or [N for hire]. Second, high voltage electricity grid systems supervisor behaves as a single unit for the purposes of wh-movement. Question–answer pairs that break it up are at the very least awkward. We related this characteristic of words to the notion of lexical integrity:

Contrast these with syntactic strings of modifier plus noun which are easily broken up, as shown in (6):
(6) Q: Which supervisor did you see?
A: The tall one.
Continuing with the notion of lexical integrity, we can ask whether it is possible to describe part of the string high voltage electricity grid systems supervisor with a modifier. When we try, the result is very awkward (7):
(7) ?A very high voltage electricity grid systems supervisor
The most natural interpretation of (7) is the figurative one whereby very high voltage is used as an adjectival phrase modifying a smaller compound [electricity grid] giving the intermediate form very high voltage electricity grid, which in turn modifies [systems supervisor], giving the entire form in (7).
Finally, we can point to the structure of high voltage electricity grid systems supervisor as evidence that it is a single noun formed by com pounding. Words in English are generally head-final, meaning that the lexical category of the form as a whole matches that of its final constituent. A dogsled is a kind of sled, not a kind of dog; the Red River Valley is a valley, not a color or a body of water; and affixed words like pollution take on the lexical category of the suffix (in this case, noun) rather than that of the stem (pollute, a verb).1 As speakers of English we know this, and without ever having heard high voltage electricity grid systems supervisor before, we know it designates a type of supervisor. Phrases, in contrast to words, are less likely to be head-final. The head of [NP John’s walking into work without a tie] is walking, not tie, and the head of [NP the house on the hill] is house, not hill.
Having established that high voltage electricity grid systems supervisor is a single word of the category N, we can ask ourselves, “Is this noun in my lexicon?” Probably not. This compound is formed by a very productive process and there is nothing irregular involved in it. It is absolutely compositional and fully motivated.
Words like this that are used but not stored are called nonce forms or hapax legomena (hapax legomenon in the singular). Nonce means ‘a particular occasion’, and hapax legomena is a Greek term meaning ‘said once’ that is used to refer to words that occur only once in the recorded corpus of a given language. These are words that somebody made up, used, and then threw away. The existence of nonce forms is one type of evidence that speakers create words on the fly as they speak.
In discussing compounds, linguists sometimes use the terms endocentric and exocentric. These terms are related to the notions of motivation and compositionality presented earlier. An endocentric compound is one that has a head. The head expresses the core meaning of the compound, and it belongs to the same lexical category as the compound as a whole. For example, goldfish is an endocentric compound. It has a head, fish, which determines both the meaning and the lexical category – noun – of the compound as a whole. Compounds whose lexical category or meaning are not determinable from the head are exocentric. Figurehead is just such a compound, because it is not a type of head. Whether a compound is endocentric or exocentric is sometimes a matter of opinion. Fabb (1998: 67) gives the example of greenhouse, which is endocentric if you think of it as a type of house, but exocentric if you do not.


1 There are exceptions to this generalization, e.g., entomb.