source / sôrs/ • n. a place, person, or thing from which something comes or can be obtained: mackerel is a good source of fish oil. ∎  a spring or fountainhead from which a river or stream issues: the source of the Nile. ∎  a person who provides information: military sources announced a reduction in strategic nuclear weapons. ∎  a book or document used to provide evidence in research. ∎  technical a body or process by which energy or a particular component enters a system.The opposite of sink² . ∎  Electr. a part of a field-effect transistor from which carriers flow into the interelectrode channel.• v. [tr.] (often be sourced) obtain from a particular source: each type of coffee is sourced from one country. ∎  find out where (something) can be obtained: she was called upon to source a supply of carpet.DERIVATIVES: source·less adj.

source In this book foods are listed as sources of nutrients. A rich source of a nutrient means that 30% or more of the recommended daily amount (see reference intakes) of the nutrient is supplied in the stated portion; a good source has 20%; and a source, 10%. Although amounts smaller than 10% are not mentioned, the foods may still make a useful contribution to the diet.

source
A. †rising on the wing;

B. fountain-head of a stream; place of origin. XIV. ME. sours(e) — OF. so(u)rs m., sourse, (also mod.) source fem., sb. uses of m. and fem. pp. of sourdre rise, spring: L. surgere rise, SURGE2
.