Definition of "sign"

(sometimes also used uncountably) A fact that shows that something exists or may happen.  quotations  examples

A mark or another symbol used to represent something.  quotations  examples

(Canada, US, Australia, uncountable) Physical evidence left by an animal.  quotations  examples

A clearly visible object, generally flat, bearing a short message in words or pictures.  quotations  examples

A wonder; miracle; prodigy.  quotations  examples

(astrology) An astrological sign.

(mathematics) Positive or negative polarity, as denoted by the + or - sign.  examples

A specific gesture or motion used to communicate by those with speaking or hearing difficulties; now specifically, a linguistic unit in sign language equivalent to word in spoken languages.  quotations  examples

(uncountable) Sign language in general.  examples

(linguistics, semiotics) a unit consisting of a signifier and a signified concept. (See sign (semiotics).)  quotations  examples

An omen.  examples

(medicine) A property of the body that indicates a disease and, unlike a symptom, can be detected objectively by someone other than the patient.  examples

A military emblem carried on a banner or standard.  quotations  examples

To make a mark

1. (transitive, now rare) To seal (a document etc.) with an identifying seal or symbol.

2. (transitive) To mark, to put or leave a mark on.  quotations  examples

   Quotations

   • Meantime revolving in his thoughtful mind / The scar, with which his manly knee was sign'd […].

     1726, Elijah Fenton, The Odyssey of Homer

3. (transitive) To validate or ratify (a document) by writing one's signature on it.  quotations  examples

   Quotations

   • Enquire the Iewes house out, giue him this deed, / And let him signe it […] .

     c. 1596–1598 (date written), William Shakespeare, “The Merchant of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, (please specify the act number in uppercase Roman numerals, and the scene number in lowercase Roman numerals)

4. (transitive) More generally, to write one's signature on (something) as a means of identification etc.  examples

5. (transitive or reflexive) To write (one's name) as a signature.  examples

6. (intransitive) To write one's signature.  examples

7. (intransitive) To finalise a contractual agreement to work for a given sports team, record label etc.  quotations  examples

   Quotations

   • Agents say Wales back Gavin Henson has signed for Cardiff Blues.

     2011, The Guardian, (headline), 18 Oct 2011

8. (transitive) To engage (a sports player, musician etc.) in a contract.  examples

To make the sign of the cross

1. (transitive) To bless (someone or something) with the sign of the cross; to mark with the sign of the cross.  quotations  examples

   Quotations

   • We receive this child into the congregation of Christ's flock, and do sign him with the sign of the cross.

     1549 March 7, Thomas Cranmer [et al.], compilers, The Booke of the Common Prayer and Administration of the Sacramentes, […], London: […] Edowardi Whitchurche […]

   • At the baptismal ceremony the child was […] signed with the cross in holy water.

     1971, Keith Thomas, Religion and the Decline of Magic, Folio Society, published 2012, page 34

2. (reflexive) To cross oneself.  quotations  examples

   Quotations

   • Shaking a fist at him with one fierce arm, / Signing himself with the other because of Christ.

     1855, Robert Browning, Men and Women

To indicate

1. (intransitive) To communicate using a gesture or signal.  quotations  examples

   Quotations

   • I signed to Brown to make his retreat.

     1815 February 24, [Walter Scott], Guy Mannering; or, The Astrologer. […], volumes (please specify |volume=I to III), Edinburgh: […] James Ballantyne and Co. for Longman, Hurst, Rees, Orme, and Brown, […]; and Archibald Constable and Co., […]

2. (transitive) To communicate or make known (a meaning, intention, etc.) by a sign.  examples

3. (transitive) To communicate using gestures to (someone).  examples

4. (intransitive) To use sign language.  examples

5. (transitive) To furnish (a road etc.) with signs.  examples

To determine the sign of

1. (transitive) To calculate or derive whether a quantity has a positive or negative sign.  examples