Cold email glossary
40 terms you meet running outreach — warmup, catch-all, bounce rate, sending window and the rest — each explained in plain language, with how it shows up in MailFleet.
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Catch-all domainA domain whose mail server accepts email to any address, so verification can't tell you whether a specific mailbox exists.Cold emailAn unsolicited but personal email to someone you have no prior relationship with, sent one-to-one at low volume to start a conversation.Cold outreachContacting prospects who don't know you, across one or more channels — email, LinkedIn, phone — to start a sales conversation.Company pause (domain pause on reply)Pausing every contact at a company when any one of them replies, so a "please stop" from one person isn't followed by a pitch to their colleague.Custom tracking domainServing open-pixel and click-tracking links from a subdomain you own (trk.yourdomain.com) instead of the tool's shared tracking host.
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Daily sending limit (per mailbox)The maximum cold emails a single mailbox sends per day — 20 to 50 in practice, far below the provider's technical cap.Dedicated sending IPAn IP address used only by your mail, so your reputation isn't shared with other senders on the same infrastructure.DeliverabilityWhether your email reaches the inbox (rather than spam, or nowhere) — the product of authentication, reputation, volume, list quality and content.DKIMDomainKeys Identified Mail — a cryptographic signature your mail provider adds to each message, verified against a public key published in your DNS.DMARCA DNS policy record that tells receivers what to do when SPF and DKIM fail or don't align with the From domain, and asks them to send you reports.Domain warmupBuilding reputation for a brand-new sending domain — DNS records first, then mailbox warmup, then cold volume ramped over about four weeks.
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Email authenticationThe set of DNS-based checks — SPF, DKIM and DMARC — that let a receiving server verify an email really came from the domain it claims.Email verificationChecking whether an address exists — by asking its mail server — before you send to it, to keep bounces under 2%.Email warmupSending ordinary emails between real inboxes that open, reply and rescue them from spam, so a new mailbox builds sending reputation before cold outreach begins.
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Mailbox rotation (inbox rotation)Spreading one campaign's sends across many connected mailboxes so no single sender exceeds its daily limit.Multichannel sequenceOne sequence mixing email steps with LinkedIn actions (visits, connection requests, messages) and calls, so a prospect meets you on more than one channel.
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One-click unsubscribeThe RFC 8058 List-Unsubscribe headers that let a recipient opt out with one click from their mail client; required by Gmail and Yahoo for bulk senders.Open trackingDetecting that an email was opened by embedding an invisible image that loads from a tracking server — increasingly unreliable and a spam signal in cold email.Out-of-office handlingReading the return date from an auto-reply and holding the next step until then, instead of ending the sequence or sending into an empty inbox.
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Send gap (throttling)The minimum time between two emails from the same mailbox, randomised so sends don't fall on a fixed interval.Sender reputationA receiving provider's running score of a sending domain and IP, built from how recipients treat its mail — opens, replies, deletions, spam reports, bounces.Sending domain (lookalike / secondary domain)A domain used only for outreach, separate from your primary company domain, so cold email reputation never affects your normal mail.Sending windowThe hours and days during which a campaign is allowed to send, usually business hours in the recipient's timezone.Sequence (cadence)A series of timed steps — emails, LinkedIn actions, calls — sent to a prospect in order until they reply.Soft bounceA temporary delivery failure — full mailbox, greylisting, a policy or reputation rejection — that can be retried later.Spam rate (complaint rate)The share of your delivered mail that recipients mark as spam; Gmail says keep it below 0.3% and ideally under 0.1%.SPFSender Policy Framework — a DNS TXT record listing which servers may send email for your domain.SpintaxSyntax like {Hi|Hey|Hello} that picks one alternative per send, so no two emails from a sequence are byte-identical.Stop on replyThe rule that any inbound reply from a prospect immediately cancels every remaining step of their sequence, before a human reads it.SubsequenceA short follow-up sequence that starts automatically when a reply is tagged with a chosen intent — for example, sending the calendar link on a meeting request.Suppression list (blocklist)Addresses and domains that must never be emailed — unsubscribes, complaints, bounces, competitors — enforced at import, enrolment and send time.