A box or draw which you can literally ' Drop ' things in. Drop Box's are useful for storing important things, for example a Drop Box could contain things like you phone, wallet and other things that are important. Drop Box's are used in garages to store tools that are needed on a regular basis.
"Where it the spark plug spanner?"
"In the Drop Box"
"Where did i leave my phone?"
"oh, i put it in the Drop Box"