syn- /sin-/, sy- /si-/, syl- /sil-/, sym- /sim-/ or sys- /sis-/

Signifying together, with

• housecrafts
• housed
• house-dog
• house-dogs
• house-duties
• house-duty
• house-factor
• house-factors
• house-father
• house-fathers
• house flag
• house flags
• houseflies
• housefly
• houseful
• housefuls
• house group
• house guest
• house guests
• household
• Household Cavalry
• householder
• householders
• household franchise
• household gods