Quote "No-one but Adobe understands why Adobe insists on referring to Lightroom as both Adobe Lightroom and Adobe Photoshop Lightroom."
Up to a few months before Lightroom was released in the market and still in "Beta" mode the decision was made to change the name from "Adobe Lightroom" to "Adobe Photoshop Lightroom". This was a poor decision on Adobe's part and has led to confusion to what Lightroom is as a product.
Lightroom is in effect an alternative to "Bridge and the Adobe Camera Raw Plugin" that is available for the use in Photoshop CS and Photoshop Elements.
Lightroom is not Photoshop and the inclusion of the name only causes confusion.