Definition of "contagious"

contagious

/kənˈteɪdʒəs/

adjective
comparative more contagious, superlative most contagious
1. (of a disease) Easily transmitted to others.
2. (figurative) Easily passed on to others.
  Quotations
  The taverns of our ancestors would ill bear contrasting with the clubs of to-day; but many a gay midnight was past in the former:—midnights, whose mirth has descended even to us; half the jests, whose gaiety is still contagious; half the epigrams, whose point is yet felt, were born of those brief and brilliant hours.
  1837, L[etitia] E[lizabeth] L[andon], “Success”, in Ethel Churchill: Or, The Two Brides. […], volume II, London: Henry Colburn, […], page 75
  Cause love is contagious, when it's alright / Love is contagious, when it's alright / Love is alright
  2000, Damon Gough (lyrics and music), “Magic in the Air”, in The Hour of Bewilderbeast, performed by Badly Drawn Boy
3. (of a person) Having a disease that can be transmitted to another person.
4. Contiguous.
  Quotations
  In Agypt's land contaygious to the Nile / Old Pharao's daughter went to bathe in style,
  19th century, Zozimus (lyrics and music), “The Finding of Moses”