Synonyms
Synonyms teach search that different words should find the same products. Relvello already handles plurals and typos, so you only need synonyms for genuinely different words.
Manage them on Merchandising › Search › Synonyms.
Same meaning
A group of words that are interchangeable. A search for any one of them finds products matching any of the others.
Example: tee, t-shirt, tshirt
One way
A word that also finds other words, but not the other way round. Use it when one term is broader, or when shoppers use a word your catalog doesn't.
Example: jumper also finds sweater. Searching "sweater" doesn't bring up products that
only say "jumper".
Finding words to add
The Analytics page lists Searches that found nothing, with a link to Synonyms. Those are the best place to start.
Limits
Up to 300 same-meaning groups and 300 one-way rules. Changes go live when you save.