Your catalog says "headset." The customer searches "headphones." The product exists, but search returns nothing. Not because it's broken — because "headphones" and "headset" are different words as far as the algorithm is concerned. It doesn't know they mean the same thing to a human. Over a month, this gap between catalog language and customer language can cost you 20–30 orders you'll never see in analytics. Synonyms are how you teach search to understand your customers' words, not just your catalog's.
Why Customers and Catalogs Speak Different Languages
Store owners name products for inventory or industry convention. Customers search the way they talk in everyday life. These are two different vocabularies — and there's always a gap.
| Catalog Language | Customer Language |
|---|---|
| Headset | headphones, earbuds, earphones |
| Sneakers | trainers, running shoes, athletic shoes |
| Portable charger | power bank, battery pack, external battery |
| Stroller | pushchair, pram, buggy |
| Dishwashing liquid | dish soap, washing-up liquid |
| Air fryer | air oven, convection fryer |
| Comforter | duvet, blanket, quilt |
None of these queries are mistakes. The customer is searching correctly — from their point of view. Search without synonyms simply doesn't know these connections exist.
Three Types of Synonyms — and Why They're Different
Direct synonyms — words that mean the same thing
"Headphones" = "earbuds" = "earphones." Any of these should find the same products. This is the simplest type — a two-way link: search any word, find everything.
One-directional synonyms — broader and narrower terms
"Sneakers" → finds "Nike Air Max 90," but not the other way around: searching "Nike Air Max 90" shouldn't show every sneaker in the store. Or "phone" → shows both "smartphone" and "mobile phone," but "smartphone" doesn't necessarily show basic phones.
This is the most common mistake when adding synonyms in bulk — making every connection two-way. The result: someone searches for a specific model and sees the entire category. If you don't configure directionality separately, search results become noisy fast.
Industry jargon that customers don't use
Technical terms that shoppers don't know or confuse. "Water heater" and "boiler" — most people consider them the same thing, but one is technical and the other is everyday language. "Air fryer" and "convection oven" — different names for overlapping products depending on the brand. A customer searches "air oven" and your catalog only has "air fryer" — zero results.
Every niche has its own set. In hardware stores: "drill" and "driver" and "drill/driver." In baby products: "stroller" vs. "pushchair" vs. "pram" vs. "buggy" — four words for the same thing depending on where your customer is from. In pet stores: "pet food" and "dog food" and "kibble." These connections seem obvious to you — but search doesn't know them.
Where to Get Synonyms — Three Sources That Actually Work
Source 1 — Zero-Result Analytics
The most valuable source. Open your "queries with no results" report and you'll see the exact words customers search and find nothing. Some of these are synonyms for products that exist in your catalog.
For example: 15 people last month searched "iPhone charger" and found nothing — because your catalog has "Lightning cable" and "Apple charging adapter." One synonym — and 15 customers per month see products instead of an empty page.
Spefix shows this report right in the dashboard, no Google Analytics configuration needed.
Source 2 — Top Search Queries With Low Conversion
Look at queries that return results but have poor conversion. This can mean people find something — but not what they wanted. The query "wireless charger" shows cables and adapters because the word "charger" is in the names — but the customer wanted a Qi charging pad. Analyze the mismatch and adjust synonyms or product names.
Source 3 — Common Sense and Niche Knowledge
Think about how your customer talks in real life. If you sell home goods — does an average person know the difference between a "comforter" and a "duvet"? If not, make them synonyms.
Simple test: ask someone outside your industry to find three products on your site. The words they use are your potential synonyms.
Start with the top 20 zero-result queries from last month — that alone will make a noticeable difference.
How to Set Up Synonyms in Spefix
Spefix includes a built-in synonym dictionary covering the most common e-commerce categories: home appliances, clothing and footwear, cosmetics, electronics, home goods, sports, kids' products, and more. It works automatically from day one — no extra setup required.
Supported languages: Ukrainian, Russian, English, German, Spanish, Polish — and the list is growing. If you're reading this after spring 2026, language support may already be broader.
What it doesn't cover: highly specialized terminology for your specific niche, regional slang, or audience-specific jargon. That's manual configuration. In practice, most stores need 50–150 synonym connections to close 80% of problem queries.
Common Mistakes
Separate pairs instead of groups. Added "headphones = headset" and "earbuds = headset" separately. Seems right. But someone searching "headphones" doesn't find "earbuds" — because those two aren't linked directly. Creating separate pairs is bad practice: you'll end up with duplicates that are hard to manage. Better to keep multiple synonyms in one synonym row: "headphones = headset = earbuds" — one group, all words connected.
Synonyms that are too broad. Someone added "electronics = tech." Now searching "tech" returns everything from phones to kettles. Synonyms should be specific — at category or product level, not mega-category level.
Synonyms instead of better product names. Sometimes it's better to rename the product or add an alternative name to the description. If "portable charger" is constantly searched as "power bank" — maybe add "power bank" to the product title.
Not testing the result. Added the synonym "cover = case" — and now "case" shows phone covers instead of suitcases and tool cases. One untested synonym can break results for an entire category. After every new synonym, test the query on your site manually.
Synonyms vs. Morphology vs. Fuzzy Search
Three tools that often get confused:
Morphology — handles forms of the same word. "Shoe," "shoes," "shoe's" — same word, different forms. Grammar, not synonyms.
Fuzzy search — handles typos and misspellings. "Headphons" instead of "headphones" — that's an error, not a synonym.
Synonyms — handle different words with the same meaning. "Sneakers" and "trainers" — different words, same product.
A properly configured search uses all three simultaneously and invisibly to the customer. If you only have synonyms but no morphology, a search for "trainers" (plural) might not match a product titled "trainer" (singular).
When to Update Your Synonym Dictionary
- Once a month — review new zero-result queries. Are there words that should become synonyms?
- When adding new categories — new products bring new terminology. Add obvious synonyms immediately.
- During seasonal shifts — "Christmas gift," "Valentine's present," "back to school" — seasonal query clusters that need separate attention. Customers search differently before Black Friday than they do in February.
If you don't want to deal with synonyms manually — try Spefix. The built-in synonym dictionary works from day one. And beyond synonyms, Spefix automatically handles typos and misspellings, brand transliteration and keyboard layout correction for supported languages, morphology, and much more. No developer needed, no changes to your site.
Try free for 14 days → spefix.com