noun

• (academia) An examination, given often during the academic term.
• (cricket, normally "Test") A Test match.
• (marine biology) The external calciferous shell, or endoskeleton, of an echinoderm, e.g. sand dollars and sea urchins; testa.
• (botany) Testa; seed coat.

verb

• (academics) To administer or assign an examination, often given during the academic term, to (somebody).
• (copulative) To be shown to be by test.
  "He tested positive for cancer."
• (chemistry) To examine or try, as by the use of some reagent.
  "to test a solution by litmus paper"
• (intransitive, transitive, slang) To challenge (someone) to a fight.
  "Back then, you couldn't rock any type of jewelry just like that, because someone was going to test you or rob you. If you were wearing a chain, you had to be someone who was known for shooting or cutting or knocking dudes the fuck out. And someone who didn’t know you may still try and test, so you couldn't really rely on your rep to save you every time."

noun

• (obsolete) A witness.
  "1523-1525, John Bourchier, 2nd Baron Berners, Froissart's Chronicles Prelates and great lords of England, who were for the more surety tests of that deed."

verb

• (obsolete, transitive) To attest (a document) legally, and date it.
• (obsolete, intransitive) To make a testament, or will.