sap / sap/ • n. the fluid, chiefly water with dissolved sugars and mineral salts, that circulates in the vascular system of a plant. ∎ fig. vigor or energy, esp. sexual vitality: the hot, heady days of youth when the sap was rising.• v. (sapped, sap·ping) [tr.] gradually weaken or destroy (a person's strength or power): our energy is being sapped by bureaucrats and politicians. ∎  (sap someone of) drain someone of (strength or power): her illness had sapped her of energy and life.DERIVATIVES: sap·less adj.sap² • n. hist. a tunnel or trench to conceal an assailant's approach to a fortified place.• v. (sapped, sap·ping) [intr.] hist. dig a sap or saps. ∎  [tr.] archaic make insecure by removing the foundations of: a crazy building, sapped and undermined by the rats. ∎  [tr.] [often as n.] (sapping) Geog. undercut by water or glacial action.sap² • n. inf. a foolish and gullible person: He fell for it! What a sap!sap³ inf. • n. a bludgeon or club.• v. (sapped , sap·ping ) [tr.] hit with a bludgeon or club.

Sap

SAP. Underground gallery dug to get beneath fortifications, usually for the purpose of blowing a mine. It is also a trench pushed toward the enemy by digging at the saphead (head of the sap) while using the trench for defilade. If the earth is thrown to one side for additional protection, it is known as a full or single sap; if dirt is thrown to form parapets on both sides, it becomes a double sap. A flying sap is one constructed under fire by using two gabions for cover and pushing them forward, side by side, as the work progresses. A sap roller is a gabion rolled forward to protect the sappers as they work. A sapper is a military engineer trained not only for this type of siege work but also for other varieties of field fortification.

SEE ALSO Gabion.

sap2 †undermining a defence; construction of covered trenches to approach a besieged place XVI; trench so constructed XVII. Early forms zappe, sappe — It. zappa and the derived F. †sappe, †zappe (now sape) spade, spadework.
Hence sap vb. dig a sap XVI; undermine XVII; weaken insidiously (assoc. with SAP1, as if ‘drain the sap from’) XVIII. — F. saper, †sapper — It. zappare.

sap
1. The sugary fluid that is found in the phloem tissue of plants. Sap is the medium in which carbohydrates, produced in photosynthesis, and other organic molecules are transported and stored in plants.

2. (cell sap) The fluid that is contained in the vacuoles of plant cells. It is a solution of organic and inorganic compounds, including sugars, amino acids, salts, pigments, and waste products.

sap The exudate from ruptured tissues emanating from the vascular system or parenchyma. See also LATEX and RESIN.