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

Signifying together, with

• estimations
• estimative
• estimator
• estimators
• estipulate
• estival
• estivate
• estivated
• estivates
• estivating
• estivation
• estivations
• estoc
• estocs
• estoile
• estoiles
• Estonian
• estop
• estoppage
• estoppages
• estopped
• estoppel
• estoppels
• estopping
• estops