Rank well for singular keyword, don't exist for the plural

[SoleDrag]

We recently redesigned our website, and lost some rankings. This is to be expected, but here is what is baffling me the most:

We rank well for "golf widget" - #3 overall. But when it comes to "golf widgets" we don't exist. Like not even in the top 500. It hurts because that the more popular phrase by far.

How could the "S" make that much ranking difference? Anything I'm missing?

[seoholic]

Maybe HTML5 tags can help?
Has anyone made experiences with using the following tags?
abbr
details
dt

[Robert Charlton]

Plurals are generally much more frequently searched than singulars and therefore are usually more competitive. Check the Google Adwords suggestion tool for your specific phrase. Use exact match, not broad match, when you use the tool.

What form is used in your title, on your page, and in inbound link anchor text... singular or plural? What are your competitors doing?

All other things being equal, Google will generally stem a word, but all other things usually aren't equal. Pages targeting the plural, or doing a better job of it than you are, are going to beat you.

[netmeg]

I run into this all the time. Even worse, it's entirely possible for AdWords to give me a QS of 10 on a singular and a 6 on a plural (or vice versa) Really annoying; Google is nowhere near as good at this as they ought to be.

[seoholic]

Google also can't handle abbreviations or synonyms correctly.
Example: plane,airplane,aeroplane,aircraft... you get very different results and especially very different technical sites.

[Robert Charlton]

Just to play devil's advocate here... on the one hand, we complain about Google rewriting our queries (I know I do), and on the other, some of us want Google to rewrite our targets. Can't have it both ways, IMO.

Conceivably, the spelling and singular/plural differences serve useful functions. And for some webmasters, intentionally targeting misspellings had been a useful source of traffic.

[tedster]

I know for some keywords at least, there is a marked difference in buying intent or informational intent between the singular and the plural. Usually the one that is more competitive will also carry a higher buying intent.

Google seems to have an extensive taxonomy of query intentions at work, and that can well mean that your page will not rank well for both, depending on its classification.