A definition that holds up
Cold email is a short message sent to a professional who has not heard of you, proposing one specific thing and asking one question. The contact is chosen because their company has a problem you solve, and the message says so in plain words.
It is a B2B practice. The sender is a company, the recipient is a person acting for a company, and the subject is business. That distinction matters legally and practically.
What it is not
It is not spam. Spam is the same message sent to anyone whose address exists. A cold email goes to a few hundred people chosen for a reason, from a real sender, with an honest subject line and an easy way to say no.
It is not a newsletter. A newsletter goes to people who asked for it. Cold email goes to people who did not, which is why it has to be shorter, more specific and more polite.
It is not mass mailing. The tools can send thousands a day. The method works at a few dozen per mailbox per day, because inbox providers watch volume and because a list of ten thousand cannot be precise.
What a good one looks like
Under a hundred and twenty words. Plain text, no images, no attachments, often no link in the first message. A first line that shows you know what the recipient’s company does. One sentence about what you offer and for whom. One question. A signature with a real name and a way to reach you.
Then two follow-ups, a few days apart, each adding one new reason rather than repeating the first.
What it can do
Done this way, a campaign tells you within a month whether a market wants what you sell. Reply rates in the twenties and thirties are normal on precise lists; a few percent of a list turns into meetings. For a small company that is often more pipeline than any other channel produces in the same time.
What it cannot do
It cannot sell something nobody understands in two sentences, and it cannot rescue an offer that is not competitive. It also cannot run from your main domain without risk, which is the subject of another article.