The idea of the gloss tags was based on the original star idea: single words were starred, on the basis that they would be used to create a simple word-list in English. Phrases couldn't be starred, because there's no way to know when the phrase would end, so the original starring was restricted to single words. Our gloss tags are doing the same sort of thing, but now, if you want to put a phrase in a gloss tag, you're welcome to do that. However, bear in mind that what you're creating with a gloss tag is an entry in a simple English-Moses dictionary; if you wrap a phrase such as "a small cup" in a gloss tag, then that entry will show up under "a" in the E-M dictionary, which is presumably not what you want. In other words, the gloss tags reproduce exactly what was available in the original star system (they identify a single word that will be used to create an E-M wordlist); but they aren't restricted to a single word, as the starring system was.