(manufacturing) Initialism of surface insulation resistance. / (biochemistry, genetics) Abbreviation of silent information regulator.

(epidemiology) Initialism of susceptible-infected/infectious-removed/recovered.

Alternative letter-case form of sir. / (Britain) The titular prefix given to a knight or baronet.

Abbreviation of Sirach.

To address (someone) using "sir".

form of address to a man you respect

simple past tense and past participle of sir

present participle of sir

plural of sir

Third-person singular simple present indicative form of sir