Thistles - definition of Thistles by The Free Dictionary

this·tle (thĭs′əl) n. 1. Any of numerous often weedy plants of several genera of the composite family, including Cirsium, Carduus, and Onopordum, having prickly leaves and floral bracts. 2. Any of various other prickly plants, such as Russian thistle. [Middle English, from Old English thistel; see steig- in Indo-European roots.] thistle (ˈθɪsəl ...…