A schoolteacher.
A senior school student, especially a school-leaver, engaged in unsupervised celebrations during schoolies week.
An education officer.
A juvenile gamefish (especially striped bass) at a stage where it tends to swim with others in schools rather than stay to itself.
to a teacher.
A man of a higher rank or position.
to a knight or other low member of the peerage.
to a superior military officer.
A respectful term of address to a man of higher rank or position
A respectful term of address to an adult male (often older), especially if his name or proper title is unknown.
To address (someone) using "sir".