- any of various prickly, composite plants having showy, purple flower heads, especially of the genera Cirsium, Carduus, or Onopordum.
- any of various other prickly plants.
- any of numerous plants of the genera Cirsium, Carduus, and related genera, having prickly-edged leaves, pink, purple, yellow, or white dense flower heads, and feathery hairs on the seeds: family Asteraceae (composites)
- a thistle, or a representation of one, as the national emblem of Scotland
- See Order of the Thistle
- (sometimes not capital)
- the emblem of this Order
- membership of this Order
