A plain-language ecommerce terms glossary

Twenty words you'll hit while setting up a store or reading about one, defined in a sentence or two — no account required, no "read the full guide" gate.

Most of these words aren't hard once someone explains them once; the trouble is that most explanations assume you already know five other words first. This page doesn't. Every term below is defined in plain sentences, grouped by where you'll actually run into it — running the shop, or getting the shop found in search — and each one links to a deeper guide where a short definition genuinely isn't enough. The search-related terms are also covered end to end, together, in the on-page SEO checklist.

Jump to a term Selling online: SKU · Payment gateway · Checkout · Capture (payment) · Reverse charge & VIES · Gift card · GMV · AOV · Cohort · Fulfilment

— Stock keeping unit: a unique code for one exact version of something you sell. A jumper in "blue, size M" and the same jumper in "blue, size L" are the same product but different SKUs, because you need to count and price them separately.

Payment gateway — The service that actually moves a customer's card or wallet payment and settles it into a merchant's account. Stripe, PayPal and Klarna are gateways; a store connects to one rather than becoming one itself.

Checkout — The sequence a buyer goes through from cart to paid order: contact details, shipping if anything needs shipping, payment, confirmation. Which steps appear, and in what order, usually depends on what's actually in the cart — an order of only digital items, for instance, has no reason to ask for a delivery address.

Capture (payment) — The moment an authorised payment turns into an actual charge. Immediate capture takes the money the instant an order is placed; deferred capture puts a hold on the card and only charges it later, commonly when the order ships or the work is delivered.

Reverse charge & VIES — A B2B mechanism: when a VAT-registered business in one EU country sells to a VAT-registered business in another, the seller can charge 0% VAT and the buyer accounts for it on their own return instead. VIES is the EU's own free lookup service sellers use to confirm a buyer's VAT number is genuine before relying on it. The full mechanics, including what happens if the number turns out to be wrong, are in which VAT rate to charge, and whose country's.

Gift card — Stored monetary value a customer buys once and spends later, tracked as a running balance rather than a single-use code. Unlike a discount, it behaves like cash at checkout — it can cover part of an order or all of it.

GMV (gross merchandise value) — The total value of everything sold through a store in a period, before fees, refunds, shipping or tax come off. It's a volume number, not a profit number — a store can have healthy GMV and still lose money if costs are high enough.

AOV (average order value) — Total revenue divided by number of orders in a period. A rising AOV usually means customers are buying more per visit, which is a different (and often cheaper) growth lever than getting more visitors in the first place.

Cohort — A group of customers who share a starting point, most often "made their first purchase in the same month." Cohort analysis tracks what each group does afterwards — do they come back, how often, how much do they spend the second time — which a single all-time average can't show you.

Fulfilment — Everything that happens after payment and before the customer actually has the thing: picking stock, packing and shipping for physical goods, or granting access for digital ones, with the order's status updated as each step completes.

— The short paragraph, roughly 70–160 characters at its best length, that search engines often show under a page's title in results. It doesn't move your ranking directly, but it's a big part of whether someone clicks your result over the one above or below it.

Canonical URL — The one web address you're telling search engines is the "real" version of a page, for situations where the same content could technically be reached more than one way (with or without a tracking parameter, for example). It stops near-duplicate URLs from being treated as separate, competing pages.

Hreflang — An HTML tag that tells search engines "this page has a version in another language, and here's its address." Miss the reciprocal link back, or point it at the wrong URL, and search engines may show the wrong language version to the wrong visitor — or quietly ignore the signal altogether.

Focus keyword — The one phrase you've decided a given page should be found for. Most on-page SEO checkers use it as a checklist anchor — does the title contain it, does the main heading, does the body text — rather than something transmitted anywhere; it's a target you set for your own page, not a tag search engines read directly. See how one page's score actually weighs it for the fuller mechanics.

— The single main heading of a page, distinct from the smaller subheadings under it. A page is expected to carry exactly one; zero, or several competing ones, both muddy what search engines think the page is actually about.

Slug — The part of a URL that identifies one specific page — the "online-store" in a web address ending /online-store. Short, lowercase and hyphenated reads better to both people and search engines than long, underscored or auto-generated strings of characters.

Sitemap — A machine-readable list, usually living at /sitemap.xml, of every page on a site you want search engines to know exists. It doesn't force a page into search results, but it's the fastest way to tell a crawler a page is there at all — see why a page can be published and still not show up.

Noindex — An explicit instruction on a page telling search engines "don't show this one in results," used deliberately for things like duplicate pages or account-only screens. Left switched on by accident on a page that should be public, it's one of the most common reasons a real page never appears in search.

Structured data (JSON-LD) — A block of machine-readable facts about a page — that it's an article, a product with a price, a business with an address — written in a format search engines can parse directly. It's how some results end up with extras attached, like star ratings or a breadcrumb trail, instead of just a blue link.

None of the above needs a separate plugin or a second login if the platform underneath already speaks the language. Olmira's storefront runs on real payment gateways, stored-value gift cards, and tax applied by destination at checkout: your own rate tables on any plan, and from Pro upwards an automatic EU VAT engine that charges the buyer's country standard rate from the 27-state table it ships with.

Reverse charge is the one term above the engine does not act on by itself: the storefront checkout never asks a business buyer for a VAT number, so it cannot zero-rate a B2B sale — you validate the number against VIES from your tax settings and apply the reverse charge on the invoice. The builder, meanwhile, checks every page you write against the search terms above automatically as you edit. See the online store for the selling side.