Meaning of balloon mail | Babel Free
Definitions
The transport of mail, usually for weight reasons, in the form of a postcard carrying the name of the sender by means of an unguided hydrogen or helium balloon.
uncountable
CEFR level
B2
Upper Intermediate
This word is part of the CEFR B2 vocabulary — upper intermediate level.
This word is part of the CEFR B2 vocabulary — upper intermediate level.