In guitar technique, starting a note by quickly pressing down a string with the fretting hand's finger instead of picking or finger-picking the note is called a hammer-on, and it's notated with a legato slur and a letter H. Usually this is done in a combination where a note is first picked on a string, and while the note is sounding, the same string is "hammered" on a higher fret, starting a new higher note, but with a softer attack.
However, it's not unheard of to hammer-on strings that weren't sounding previously, creating a similar effect and attack sound. I started learning the Guitar Pro notation software and was surprised that I cannot write this technique as a hammer-on, I have to write it as a "Left Hand Tapping" effect, which has a circled letter T symbol instead of H.
Is it a commonly known and accepted meaning for the term hammer-on, that a string has to have a previously sounding note in order to be hammered-on? I can understand the distinction from a programming point of view, but I wouldn't have any problem understanding the notation if it was denoted with an H and called a hammer-on.