In the Japanese language there are a few different but related names for beads. The words have "dama" in-common, and this is the part that probably indicates "a bead." The rest of the word probably modifies and distinguishes what sort of bead it may be.

In the late 1970s the first Japanese book about bead-collecting was released. It was called "Eye of the Dragonfly." (Tombodama.) So there was apparently an attempt to say that some beads look like dragonfly eyes (to some beholders). As often happens, this became corrupted, and the intent lost. And now they are just called "dragonfly beads."

In the early 1980s, Elizabeth Harris had the text of Eye of the Dragonfly translated into English. I have a copy of her translation. What it reveals is that collectors didn't and don't know much about beads, but have devised their own "jargon" for naming and describing things. And sometimes what they say may be internally inconsistent. For instance: "Roman beads from the 19th century."

JDA.