Singular and plural keywords
I’m new to AdWords and wanted to know if it was necessary to include the plural for a keyword or whether Google automatically included a search for the singular when someone searched for the plural and vise versa. What about a word like ‘canopy’ and ‘canopies’?
Re: Singular and plural keywords
Strictly speaking, I don't think it is necessary to add the plurals separately. By default, phrase and exact match types include plurals, misspellings, and other close variants.
I lifted this from the Help Centre, "With this update (of close variations), you no longer have to build exhaustive lists of misspelled, abbreviated, and other close variations of your keywords to get the coverage you want".
However, it may also be of your interest to note, other members within the community have experienced differences in performance between singular and plural queries, there are quite a few threads on here regarding this subject you may be interested in. It may be worthwhile testing the both kw variations in separate ad groups and using negative kw to control them tightly (although that approach does have supporters and opposers, but thats for another thread)
Hope that helps a little.