sir

B1 · Intermediate Countable noun British English · Formal

n. a title used before the first name of a knight or baronet.

n. the titular prefix used before the forename of a knight or baronet.

“Sir Isaac Newton was a famous scientist who studied gravity.”

“The Queen granted him a knighthood, and he is now formally addressed as Sir Anthony.”

B1 · Intermediate Countable noun British English

n. a way for students to address a male teacher in some countries.

n. a conventional term of address used by students for a male school teacher.

“Please, sir, can I go to the bathroom?”

“In many British secondary schools, it remains standard practice for pupils to address male staff members simply as 'sir'.”

C1 · Advanced Informal

v. to call someone 'sir' when you speak to them.

v. to address a person using the honorific 'sir', often to show extreme respect or military discipline.

“Don't sir me—we've been friends for years.”

“The recruit was instructed to sir every officer he encountered on the base.”