Sst

Here he found a selection of French crèmes fraîches at prices implying transport via SST.

Source: wiktionary

In and around 2016, a controversy arose when the CRPO began refusing grandparenting applications on the basis that an applicant's SST hours did not count towards fulfilling the grandparenting requirements. Specifically, the CRPO was taking the position that the 800 DCC hours requirement for grandparenting could not be satisfied with SST.

Source: wiktionary

"Sst!" hissed Mel Daggett, who was the last to enter. "Don't you know the door's open? Don't talk so loud, you fellows."

Source: wiktionary