Initialism of second impact syndrome. / Initialism of snow immersion suffocation. / (education) Initialism of student information system. / Initialism of supervised injection site.

(informal) Clipping of sister.

simple past tense and past participle of sie

(South Africa) Expressing disgust, disappointment, or annoyance.

Third-person singular simple present indicative form of sie

plural of sie

A diminutive modifier used to add an element of childishness, informality, affectionateness, or levity to a word.

forming nouns of action or process / (medicine) forming nouns of condition / forming additional nouns

plural of SI

A notification by a candidate for Holy Orders of his intention to enquire whether any impediment may be alleged against him.