MEANING: noun: A teacher, mentor, or a master in a field.

ETYMOLOGY: From Japanese sensei (teacher, master), from sen (earlier) + sei (birth), meaning a teacher was born earlier and knows more and has more experience. Earliest documented use: 1874.

SEN-SEN - the Curiously Strong Mint of the 1950s (give or take 15 years)

SENSEKI - a dramatic move in Go that had better not be made

SENASE I - the first enzyme that catalyzes activity in the Upper House of Congress