Trying to figure out why my site is ranking #5 for the term 'gas cabinets' and #12 for the singular version of it 'gas cabinet'. My best guess is it's because of the anchor texts in the backlinks. There are more anchor texts that say 'gas cabinets' than say 'gas cabinet'.. But other companies in the same field rank about the same for both plural and singular of those terms.
Site is http://www.criticalsystemsinc.com/ and page that is ranked is http://www.criticalsystemsinc.com/products/gas-cabinets
Probably due to anchor text on backlinks but could also be down to your page title containing 'gas cabinets' as its first 2 words and also on page content.
but the singular of 'gas cabinets' is 'gas cabinet' - the word 'gas cabinet' is in the title - just has an 's' at the end of it. Do you think that matters that much? they are now ranking #3 and #5 so they're a lot closer - but still the singular 'gas cabinet' is ranked below the plural.
Google will literally take your page title into account so the plural will be read as the plural, just like a human would read it.