Derived from a Greek root meaning "to put together," a symbol may be defined as a "manner of representation in which what is shown (normally referring to something material) means, by virtue of association, something more or something else (usually referring to something immaterial)" (PEPP).

Barfield's use of symbol or symbolism does not differ dramatically from the normal meaning. Witness, for example, the following passage from "Poetic Diction and Legal Fiction":

Sometimes the element of comparison [characteristic of metaphoric language generally] drops still farther out of sight. Instead of saying that A is like B or that A is B, the poet simply talks about B without making overt reference to A at all. You know, however, that he intends A all the time, or, better say that you know he intends an A; for you may have a very clear ideas of what A is and even if you have got the idea, somebody else may have a different one. This is generally called "symbolism." (RM 45)

Questions about the origin and nature of the symbolic lead inevitably to questions about the evolution of consciousness, and it is for that reason that Barfield's attention is lead to consider them. And so we find Burgeon contemplating the history of symbolism and consciousness in Worlds Apart on at least two occasions:

The ideas or images which have arisen from . . . subliminal . . . processes are just those which have the characteristics of symbols, Ritual, myth, Jung's "archetypes," poetic metaphors, and a good deal else have been ransacked and examined from this point of view, because the thing they all have in common is symbolic significance. And it is characteristic of a symbol that it has more than one meaning, often many meanings, sometimes contrasted and even opposite meanings, which are somehow reconciled within it--just the sort of thing, in fact, that can happen in the mind, but not in the material world from which the symbols are taken. Symbols are always of the inner world. (46-47)

    At first a whole generation was quite satisfied that the Greek myths, for example, were simply statements about external nature--"highly figurative conversation about the weather," as Farnell puts it. Another generation interprets them as mainly statements about the unconscious mind. Obviously they were both and neither. Go a little way farther back: dip into the Vedas and you often no longer know whether you are reading about birth and death, summer and winter, or breathing in and out. Why? Because symbolic language--and all language is symbolic in origin--can signify all these rhythms at the same time. (120-21)
See in particular Worlds Apart, passim, Poetic Diction, passim, "Poetic Diction and Legal Fiction" (RM 44-64).