We've been laying down the final plans for the honeymoon (and it's going to be awesome -- I'll have a special post up about it one of these days real soon now), so I thought I'd dig into the origin of the word...
Honey is of uncertain origin, but may go back to a Proto Indo European root something like kanek, meaning "golden". It became khunaga in West Germanic and was probably applied to "honey" at that time. (The word gold comes from a PIE root meaning "yellow / green".) In Old English it became hunig, and honey in Middle English. Spiritually it has qualities of heart and hearth, earthiness, and groundedness, but also high energy.
Moon goes back to Proto Indo European menses or meses, meaning "moon" and "month". This probably is related to the PIE root me, "measure", because the moon was of course associated with measuring time. In most daughter languages of PIE, this root was only retained for "month"; the moon itself got other names (eg selene in Greek, meaning "brightness", luna in Latin from the same root as lux, "light"). The Germanic languages, though, retained the pairing as mænon for "moon" and mænoth for "month". mænon became mona in Old English, and moon in Middle English. During this time it retained is association with time, measurement, and months. Spiritually the word evokes a manifestation of flowing, subconscious energy.
The honeymoon, then, is a month, a season, of flowing, half-conscious sweetness grounded in the heart and earth.