balloon mail
The transport of mail, usually for weight reasons, in the form of a postcard carrying…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.
Meaning
1 senses(uncountable)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.
Lessons for this word
1 lessons- A1Countable and uncountable nouns — Because it can be uncountable