English

Adjective

drop-in ‎(not comparable)

1. provided for short-term use
2. (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.

Noun

drop-in ‎(plural drop-ins)

1. One who casually drops in.
2. An informal event that does not require booking in advance.

Related terms

• plug-in