“Dharma” has a range of meanings.
At its most basic level, it refers to the teachings of the Buddha. So the body of words spilled during his 40 year teaching career, as recorded in the suttras, are “the Dharma”. You could say this is the “default” meaning of the term.
In the more esoteric sects of Buddhism—including Zen—“Dharma” takes on another dimension. Zen ascribes less weight to the suttras than does classical Buddhism. It sees the Buddha’s words as no more than one man’s attempt to direct people’s attention to the living reality unfolding moment-by-moment. The true Dharma then is reality just as it is, not so much Buddha’s remarks about it. In the Zen sense, the Buddha’s teachings are to the true Dharma as a map of Paris is to standing on the Pont Neuf.
From this derives another meaning of Dharma: Because each thing, each phenomenon in the world is in itself a manifestation of reality, things and phenomena are sometimes referred to as “dharmas”. This usage is not very common, though, because it muddles the picture.