daffodil: [16] Originally, this word was affodil, and referred to a plant of the lily family, the asphodel; it came from medieval Latin affodillus, and the reason for the change from asph- (or asf-, as it often was in medieval texts) to aff- is probably that the s in medieval manuscripts looked very like an f. The first evidence of its use to refer to a ‘daffodil’, rather than an ‘asphodel’, comes in the middle of the 16th century. It is not entirely clear where the initial d came from, but the likeliest explanation is that daffodil represents Dutch de affodil ‘the daffodil’ (the Dutch were then as now leading exponents of bulb cultivation).
daffodil (n.)
1540s, variant of Middle English affodill "asphodel" (c. 1400), from Medieval Latin affodillus, from Latin asphodelus, from Greek asphodelos, which is of unknown origin. The initial d- is perhaps from merging of the article in Dutch de affodil, the Netherlands being a source for bulbs. First reference to the flower we know by this name (Narcissus pseudo-Narcissus) is from 1590s.