User intent for a plural is usually a list of different options like a review site. A search for the plural will show yelp or yellow pages towards the top of the serp to meet the primary search intent and then in the middle will be the top pages for singular, esp if the search is on mobile as those searches have a visit intent. At the bottom of the first page serp will be definitions of the term or pages explaining what it is. Above holds true for business type keywords like roofer/roofers, restaurants/restaurant, etc.