A plant of the genus Pyracantha; the pyracanthus(noun)
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Use "firethorn" in a sentence
"Pyracantha, aka firethorn, makes a great cat-proof hedge en-masse, but as an individual it can look stunning at this time of year and does so there."
"I was moved to sing a firesong, which I made of words given me by the Hearthkeeper, and a melody given by a bird that had perched on a firethorn tree in the Kingswood."
"I gave the boys a song to hum, the same melody a bird had given me when I ate the firethorn berries in the Kingswood."