Definition of "sage"

sage¹

/seɪd͡ʒ/

adjective
comparative sager, superlative sagest
1. wise.
  Quotations
  All you sage counsellors, hence!
  c. 1596–1599 (date written), William Shakespeare, “The Second Part of Henry the Fourth, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene iv]
  commanders, who, cloaking their fear under show of sage advice, counselled the general to retreat
  1670, John Milton, “(please specify the page)”, in The History of Britain, that Part Especially now Call’d England. […], London: […] J[ohn] M[acock] for James Allestry, […]
2. (obsolete) grave; serious; solemn
  Quotations
  [Great bards] in sage and solemn tunes have sung.
  1646 (indicated as 1645), John Milton, “Penseroso”, in Poems of Mr. John Milton, […], London: […] Ruth Raworth for Humphrey Mosely, […]
noun
plural sages
1. A wise person or spiritual teacher; someone of gravity and wisdom, especially, a teacher venerable for years, and of sound judgment and prudence; a grave or stoic philosopher.
  Quotations
  We aspire to the magnanimous firmness of the philosophic sage.
  1748, David Hume, Enquiries concerning the human understanding and concerning the principles of moral, London: Oxford University Press (1973), section 34

sage²

/seɪd͡ʒ/

noun
usually uncountable, plural sages
1. The plant Salvia officinalis and savory spice produced from it; also planted for ornamental purposes.
2. Any plant in the genus Salvia
3. Any of a number of plants such as sagebrush considered to be similar to Salvia officinalis, mostly because they are small shrubs and have gray foliage or are aromatic.

sage³

/sɑɡɛ/

interjection
1. (Internet slang) Word used in the email field of imageboards to prevent a bump of the post. Used as an option rather than a word in some imageboard software.
verb
third-person singular simple present sages, present participle saging, simple past and past participle saged
1. (Internet slang) The act of using the word or option sage in the email field or a checkbox of an imageboard when posting a reply.