For any triangle ABC, six new points can be constructed by extending each of BA and CA by |BC|, each of AB and CB by |AC|, each of AC and BC by |AB|. These six points then lie on the Conway circle. Its centre is the incentre.
Conway’s circle and the incircle
- sidereal day
- sidereal month
- sidereal period
- sidereal rate
- sidereal time
- sidereal year
- Siderian
- siderite
- siderolite
- siderophile
- siderophyre
- siderostat
- side-scan sonar
- side stream
- sidewall corer
- sidewinder
- Sidgwick, Henry (1838–1900)
- Sidgwick, Nevil Vincent
- Siding Spring Observatory
- Sidufjall
- Siegbahn, Kai Manne Börje
- Siegbahn, Karl Manne Georg
- Siegel, Sidney (1916–61)
- Siegel–Tukey test
- Siegennian