| Noun | 1. | roundel - English form of rondeau having three triplets with a refrain after the first and thirdrondel, rondeau - a French verse form of 10 or 13 lines running on two rhymes; the opening phrase is repeated as the refrain of the second and third stanzas | |
| 2. | roundel - round piece of armor plate that protects the armpit | |
| 3. | roundel - a charge in the shape of a circle; a hollow roundel | |