Staple. A figure like a U inverted; thus,

.

Sudor. Sweat.

Sudoriparous. Of sweat, sweat-yielding.

Sulcus (pl. Sulci). A skin groove or furrow.

Twinned Loop. Two adjoining loops in a core, complementary in position.

Tented Arch. An arch shaped like a tent or volcanic mountain.

Terminus. A term used for distinctive points within and without a core.

Ulnar. The little finger side of the hand. (Opposed to Radial).