Airdrop
A free distribution of tokens to qualifying wallets.
Airdrops reward early users, bootstrap governance and generate attention. Eligibility is usually based on past on-chain activity, and a whole subculture of airdrop farming has grown around anticipating the criteria.
They are also a common phishing vector. Unexpected tokens appearing in a wallet often lead to a site designed to harvest approvals, and unknown tokens are best left untouched.