Anagrams of: SOURCES_

• A groove at the ends of the staves of a barrel into which the edge of the head is fitted.

• A cooper's tool for making these grooves.

• the most important point

• a small conspicuous constellation in the Southern Hemisphere in the Milky Way near Centaurus

• Cousin (usually as a term of address)

• Because

• A form of croquet using short-handled mallets, and played on a hard surface

• the helmsman of a ship's boat or a racing crew

• either of two related enzymes that control the production of prostaglandins and are blocked by aspirin

• act as the coxswain, in a boat race

• of or relating to the null set (a set with no members)

• a quantity of no importance; thing (object:), singular, negative pronoun; pronoun, thing, singular; quantifier: negative existential

• a mathematical element that when added to another number yields the same number

• the point on a scale from which positive or negative numerical quantities can be measured

• the sight setting that will cause a projectile to hit the center of the target with no wind blowing

• indicating the absence of any or all units under consideration

• having no measurable or otherwise determinable value

• indicating an initial point or origin

• adjust (an instrument or device) to zero value

• adjust (as by firing under test conditions) the zero of (a gun)