Why is my multi-word synonym not matching as expected?

Multi-word synonyms behave differently from single-word synonyms.

Matching only starts after the full phrase begins to match

For multi-word synonyms, the engine only matches the synonym when the last word starts to match. For example, with a one-way synonym:

New York > NY

• Searching for ne won’t trigger the synonym
• Searching for new yo will start triggering it

Multi-word synonyms match by sequence expression, meaning the engine considers multi-word synonyms as a single phrase and they must be in the correct order with nothing in-between.  For example, with:

NY <> New York

• A query for NY can return “New York Times”
• It will not return “new company in York”, because the exact phrase “New York” isn’t present

This also means that “New” and “York” appear in different attributes within the same records, the record wil not be returned.

An alternative solution here would be to create a Rule to rewrite the query “NY” to "New York" instead of the synonym. Please check out our documentation on Rules here keeping the Replace Word consequence in mind. This way the query HD will match records that have both "High" and "Definition", without these words needing to be in the correct order.

Impact on ranking (exact criterion)

By default, multi-word synonyms are considered "less exact" than the original query terms and so score lower than their original words on the exact ranking criterion.

For example:

distant learning <> remote learning

• Searching for “distant learning” and “remote learning” can return differently order results
• This is because “remote learning” is treated as a synonym match and scores lower on the exact ranking criterion

To ensure that multi-word synonyms are treated the same as the original terms in ranking, update the alternativesAsExact setting to include multiWordsSynonym.

This allows both the original phrase and its synonym to score equally on the exact ranking criterion.