This category is for Lojban words which would tend to be considered articles from an English speaker's perspective.
Otherwise, articles are called "descriptors" by the LRG and vlasisku, and they come in three series:
Descriptors turn brivla into sumti, i.e., they "sumtify" them.
The members of the LO series could be thought of as "indefinite articles", whereas the members of the LE and LA series could be though of as "definite articles".
For reference, see LRG Chapter 6.