Definition from Wiktionary, the free dictionary
drop-in (not comparable)
- provided for short-term use
- (manufacturing) fit to substitute some element in a complex system without changes to the existing infrastructure
- We need the ultimate drop-in biofuel to make use of our expensive oil-based infrastructure.
- 2012, Robert Mendelsohn, Ariel Dinar, Handbook on Climate Change and Agriculture, page 276
- An alternative to cellulosic based second- generation biofuels are drop-in biofuels, that is, fuels such as synthetic gasoline that can be put into fuel tanks and pipelines with no modifications.
drop-in (plural drop-ins)
- one who casually drops in.
- informal social event