difference vs driftage

difference and driftage both are nouns.

Word	Noun	Adjective	Verb	Adverb
difference	Yes	No	No	No
driftage	Yes	No	No	No

As nouns, driftage is a hyponym of difference; that is, driftage is a word with a more specific, narrower meaning than difference:

difference: a variation that deviates from the standard or norm
driftage: the deviation (by a vessel or aircraft) from its intended course due to drifting

Other hyponyms of difference include discrepancy, variance, variant, flection, flexion, inflection.

difference (noun)	driftage (noun)
the quality of being unlike or dissimilar	the deviation (by a vessel or aircraft) from its intended course due to drifting
a disagreement or argument about something important
a variation that deviates from the standard or norm
the number that remains after subtraction; the number that when added to the subtrahend gives the minuend
a significant change