# Glossary > Plain-word definitions of the cold email terms used across the Maildeck docs, from bounce to warmup. Source: https://docs.maildeck.co/glossary/ Cold email has a lot of jargon. Here's what each term means, in a sentence or two, with a link to the guide that covers it in more detail. ## B **Blacklist**: A public list of domains or servers that have been reported for sending spam. Many mail servers block or filter email from anything on it. See [Common errors](https://docs.maildeck.co/deliverability/common-errors/). **Bounce**: An email that comes back undelivered, usually because the address doesn't exist. Too many bounces damage your domain's reputation. See [List hygiene](https://docs.maildeck.co/leads-verification/list-hygiene/). ## C **Catch-all**: A domain set up to accept email for any address, real or not, so a verification tool can't confirm whether a specific person exists there. Treat these addresses as risky. See [List hygiene](https://docs.maildeck.co/leads-verification/list-hygiene/). **Cold email**: An email to someone who doesn't know you yet, usually to start a business conversation. See [Cold email basics](https://docs.maildeck.co/getting-started/cold-email-basics/). ## D **Diversified stack**: A Maildeck plan that mixes Outlook, Google and SMTP inboxes, so your sending doesn't depend on one email provider. See [Diversified stack](https://docs.maildeck.co/plans/diversified-stack/). **DKIM**: A digital signature added to every email you send, which lets the receiving server check the email really came from your domain and wasn't changed on the way. We set it up for you. See [SPF, DKIM and DMARC](https://docs.maildeck.co/domains-dns/spf-dkim-dmarc/). **DMARC**: A DNS record that tells receiving servers what to do with an email that fails the SPF or DKIM checks, for example send it to spam. See [SPF, DKIM and DMARC](https://docs.maildeck.co/domains-dns/spf-dkim-dmarc/). **DNS**: The settings attached to a domain that tell the internet where its website and email live. SPF, DKIM, DMARC and MX records are all DNS records. See [SPF, DKIM and DMARC](https://docs.maildeck.co/domains-dns/spf-dkim-dmarc/). **Domain**: The part of an email address after the @, like `getyourbrand.com`. For cold email you use brand variations, never your main company domain. See [Domains](https://docs.maildeck.co/domains-dns/domains/). ## E **Enrichment**: Filling in the details about a contact, such as their work email, job title and company. See [LeadSonar](https://docs.maildeck.co/leads-verification/leadsonar/). **EU reverse charge**: How VAT works when an EU business with a verified VAT number buys from us: we don't add VAT to the invoice, and you account for it in your own country. See [Billing, VAT and invoices](https://docs.maildeck.co/account-billing/billing-and-invoices/). ## F **Follow-up**: A later email in the same sequence, sent to someone who hasn't replied yet. See [Follow-ups](https://docs.maildeck.co/deliverability/follow-ups/). ## I **ICP (ideal customer profile)**: A description of the kind of company and person you sell to, such as industry, company size and job title. **Inbox (mailbox)**: A single email account you send from, like `jane@getyourbrand.com`. Each inbox has a safe daily sending limit. See [Inbox types](https://docs.maildeck.co/plans/inbox-types/). ## M **MX record**: A DNS record that says which mail server receives email for a domain. Without the right MX record, a domain can't receive email. See [SPF, DKIM and DMARC](https://docs.maildeck.co/domains-dns/spf-dkim-dmarc/). ## O **Open tracking**: A tiny invisible image added to an email so the sender can see when it's opened. Turn it off for cold email, especially on Outlook. See [Writing for Outlook](https://docs.maildeck.co/deliverability/writing-for-outlook/). **Outlook tenant**: A Microsoft 365 account for one domain, which can hold up to 100 mailboxes. Outlook plans are priced per tenant. See [Inbox types](https://docs.maildeck.co/plans/inbox-types/). ## P **Positive reply**: A reply that shows interest, such as "tell me more" or "let's talk", as opposed to "not interested" or an out-of-office. As a rule of thumb, expect about 1 per 200 cold emails. See [Choosing a plan](https://docs.maildeck.co/plans/choosing-a-plan/). **Pre-warmed tenant**: An Outlook tenant built on one of our own already-warmed domains, so you don't need to bring domains. Availability varies, so ask the team. See [Inbox types](https://docs.maildeck.co/plans/inbox-types/). ## Q **Quick Start**: The step-by-step order form in the Maildeck app sidebar, where you pick products, connect domains, choose your sequencer and pay. See [Your first order](https://docs.maildeck.co/getting-started/your-first-order/). ## R **Registrar**: The company you buy and manage a domain with, such as Porkbun, Namecheap or GoDaddy. See [Connect your registrar](https://docs.maildeck.co/domains-dns/connect-your-registrar/). **Role account**: A shared address like `info@` or `sales@` rather than a named person. Best removed from cold email lists. See [List hygiene](https://docs.maildeck.co/leads-verification/list-hygiene/). ## S **Sender reputation**: How much email providers trust your domain and inboxes, based on how you've sent in the past. Good reputation means more of your emails reach the inbox. See [Warmup](https://docs.maildeck.co/deliverability/warmup/). **Sequencer**: The tool that sends your campaigns and follow-ups on a schedule, such as Instantly, Plusvibe, Smartlead, EmailBison or Manyreach. You sign up with the vendor; we connect your inboxes to it. See [Connect your sequencer](https://docs.maildeck.co/getting-started/connect-your-sequencer/). **SMTP**: The standard way email is sent between servers. At Maildeck, "SMTP inboxes" are low-cost inboxes on private mail servers, rather than on Outlook or Google. See [Inbox types](https://docs.maildeck.co/plans/inbox-types/). **Spintax**: A way to write several versions of a phrase in one template, so each email comes out slightly different, for example "Hi" in one and "Hello" in another. It helps avoid looking like a mass mailing. See [Writing for Outlook](https://docs.maildeck.co/deliverability/writing-for-outlook/). **SPF**: A DNS record that lists which servers are allowed to send email for your domain. We set it up for you. See [SPF, DKIM and DMARC](https://docs.maildeck.co/domains-dns/spf-dkim-dmarc/). **SRT (Scaling Room EcoTokens)**: The tokens you earn through the referral programme, worth one dollar each. See [Referral programme](https://docs.maildeck.co/account-billing/referral-programme/). ## U **Unsubscribe**: When someone asks you to stop emailing them. Remove them from every campaign straight away. See [List hygiene](https://docs.maildeck.co/leads-verification/list-hygiene/). ## V **Verification**: Checking each address on a list before you send, to remove ones that don't exist or are risky. See [EmailShield](https://docs.maildeck.co/leads-verification/emailshield/). ## W **Warmup**: A period where new inboxes send and receive a small, growing number of friendly emails, so providers learn to trust them before you start cold sending. We run it for you. See [Warmup](https://docs.maildeck.co/deliverability/warmup/).