You know what that tool is? It is an icon of every plumber stereotype there is. You take a picture of a guy with one of those in his hands and you immediately think "plumber". I'm sure they hand them out at the end of plumber school along with the catalog of clothing that will show butt cracks by the inch.
Do you know what it's called though? Pipe wrench? Nope. While that is a nickname, it is actually called a Stillson wrench. You probably didn't know that, because most people don't. Daniel Stillson invented it about 140 years ago. That longevity alone is pretty impressive. Then again I was always impressed the Monkey Wrench was invented by Charles Moncky.
Think about how different people would search for a Stillson wrench online. Plumbers are going to aim straight for what they need. They are what we call a "knowledgeable researcher", they will enter a size, material, brand, model or other information. They are looking for the best price and they know exactly the requirements their potential search results should have. However I could add a "super-" to "knowledgeable researcher" because a plumber would be a professional consumer of a wrench. They will have more knowledge about the product than another type of consumer, ie the homeowner.
I want to buy stock in Brand X
Plumbers are going to know that "brand Y" is expensive and cheaply made and while "brand X" may also be expensive, it will last forever. Homeowners are going to be regular researchers, trying to figure out how to do a home repair just to find out that this funny looking wrench is needed. One of these searchers has a need that comes from earned knowledge, the other from researched knowledge.
These two users intersect at your site. They start on Google and contrary to what every boardroom web jockey (BWJ) will think, the first phrase they put into Google wasn't "wrench". BWJ will put "wrench" into Google and ask why their site isn't #1.
No one does searches that way. You didn't search for "car" the last time you bought one, just the same way you didn't Google "vacation" the last time you went on one. Which is a great way to enlighten those BWJ's who invariably seem to sign checks.
In fact, I will go so far as to say our two users, the plumber and the homeowner who are both in my area for the sake of argument, didn't search for "pipe wrench" or "Stillson wrench" at all. They looked for "tool store in wichita, kansas", "plumbing supply" or "hardware stores near 67202". In this case they looked for what they needed, not what a site has.
You have to talk like the animals
However there is another issue, being too focused on industry terms. Much the same way a bride-to-be isn't looking up "bridal clothing supply" or "matrimonial apparel". You have to recognize when there is a disconnect between your industry terms and layman terms. I'm not advocating that you don't use industry terms. Those terms likely help Google determine your vertical placement, or in real people language; it helps Google figure out that a site is a plumbing site because it uses plumbing industry terms. Read your analytics, they will tell you how people are finding your site. Filter out your name and repeat visitors and see what people are putting in to really "find" you. Those are the people that may have no idea that you exist and you need to capture them.
As an exercise with new customers we put their name into a search engine and see what comes up. The number one search term for any site has always been on it's name. If a site can't rank on the company name, they can't expect to rank well on anything else. Which is great up to a point. I've tackled sites that their top 50 terms all had their name as part of the term. Which means your company name is drowning out your business.