what dose Airdrop mean?

The term airdrop is sometimes used to describe the process of distributing tokens to wallets. For example when the network of an ICO or fork goes live the newly created token might be airdropped to wallets of existing coin holders.

Meaning: Airdrop is an ICO distribution method that occurs via a hard fork attempt, free of charge. Airdrops can come as a surprise or be announced beforehand.