There are two derivations of the name. One is that of the youth of Greek mythology called Narcissus, who, in at least one of many variations of the tale, became so obsessed with his own reflection as he kneeled and gazed into a pool of water that he fell into the water and drowned. In some variations, he died of starvation and thirst from just sitting by the edge of the pool until he gave out, gazing at his reflection until he died. In both versions, the Narcissus plant first sprang from where he died. The other derivation is that the plant is named after its narcotic properties (narkao, to numb in Greek).
Narcissus 'Geranium'
There are several plurals in common use: "Narcissuses", "Narcissi", and "Narcissus". This last is common in American English but is very rare in British usage. The American Webster's Third New International Dictionary gives plurals in the order "Narcissus", "Narcissuses", and "Narcissi", but the British Compact Oxford English Dictionary lists just "Narcissi" and "Narcissuses".
The name Daffodil is derived from an earlier "Affodell", a variant of Asphodel. The reason for the introduction of the initial "d" is not known, although a probable source is an etymological merging from the Dutch article "de," as in "De affodil." From at least the sixteenth century "Daffadown Dilly", "daffadown dilly", and "daffydowndilly" have appeared as playful synonyms of the name.
The name jonquil is sometimes used in North America, particularly in the South, but strictly speaking that name belongs only to the rush-leaved Narcissus jonquilla and cultivars derived from it.
Flowers of the tazetta-group species Narcissus papyraceus are commonly called paperwhites.
All Narcissus species have a central trumpet-, bowl-, or disc-shaped corona surrounded by a ring of six floral leaves called the perianth which is united into a tube at the forward edge of the 3-locular ovary. The seeds are black, round and swollen with hard coat. The three outer segments are sepals, and the three inner segments are petals. Though the traditional daffodil of folklore, poetry, and field may have a yellow to golden-yellow color all over, both in the wild species and due to breeding, the perianth and corona may be variously colored. Breeders have developed some daffodils with double, triple, or ambiguously multiple rows and layers of segments, and several wild species also have known double variants.
credit: http://en.wikipedia.org/wiki/Narcissus_(plant)