I rarely use the store search; I prefer using the "seller's other items" link for searching, as I find it gives me more options, such as allowing me to choose worldwide item locations rather than the default. Those sorts of filters and options are not available in a store search.
Using the "seller's other items" link, I see six listings with books in the title, and the enciclopedia also turns up when searching that term. Normally when a slight variation in a keyword produces more results, eBay's search will substitute the more popular keyword and tell you that is what is being searched and give you a link for the original keyword, but if you are searching within a store the interface is different and it may not make the substitution apparent.
When searching suede I get one result, plus one item "matching fewer terms", which is odd since I am only searching the one term. In some cases, eBay apparently does some odd keyword grouping -- so it is possible that faux suede is treated as a keyword distinct from suede. But both items contain the term faux suede, so it is not clear what the distinction between the two listings is in this case. Perhaps the grouping applies only if the words are nearer the start of the item title; I am not certain how that works.
There are ways to force eBay's search to find exact matches rather than grouped or substituted keywords; you can put one of your keywords in quotes or add an exclusion term to bypass many of the search expansion features. Indeed, searching "suede" or "enciclopedia" using the quotes will find all those items in your store.
Knowing these workarounds -- while useful -- will not necessarily help your potential buyers find your items in your store, however, unless they know the workarounds, too.
But if someone is doing a general search (as opposed to a store search) for an enciclopedia, they will quickly realize that eBay is substituting encyclopedia instead, and they can decide which term they prefer.
