sentinel (sen'ti-nel), soldier set to guard an army or camp.
sentry (sen'tri), guard.
sepulchre (sep'ul-ker), grave; bury.
seraglio (se-ral'yo), a harem.
seraph (ser'af), an angel.
serenity (se-ren'i-ti), calmness.
serf (surf), a slave bound to work on a certain estate and sold with it.
servile (sur'vil), like a slave; cringing.
session (sesh'un), meeting.
sesterce (ses'ters), an ancient Roman coin.