It consists of small clusters of four copper atoms each, supported on a thin film of aluminum oxide. (sciencedaily.com)
Although similar to onions, shallots grow in small clusters of bulbs on one plant (more like garlic). (styleathome.com)
But when you start chatting back and forth, the other person is typing recognizable words along with small clusters of letters here and there. (datingsitesreviews.com)