1. (biology) an artificial taxonomic category for organisms of which the true relationships are obscure

Type of: family

• sidewinder
• sidewise
• siding
• sidle
• sidle up
• Sidney
• Sidney Caesar
• Sidney James Webb
• Sidney Poitier
• Sidney Webb
• Sidon
• Sidonie-Gabrielle Claudine Colette
• Sidonie-Gabrielle Colette
• SIDS
• siege
• siege of Orleans
• siege of Syracuse
• siege of Vicksburg
• siege of Yorktown
• Siege Perilous
• Siegfried
• Siegfried line
• siemens
• sienna
• sierra