Definition of "heirloom"

heirloom

/ˈɛə.luːm/

noun
plural heirlooms
1. A valued possession that has been passed down through the generations.
2. (horticulture) An old crop variety that has been passed down through generations of farmers by seed saving and cultivation, in contrast to modern cultivars used in large-scale agriculture.
  Quotations
  My last trip to the market barely yielded enough unmealy heirlooms for a couple of salads.
  2009 August 19, Melissa Clark, “Plums Rescue a Seasonal Favorite”, in New York Times‎
  At Hortus Bulborum you will find heirloom narcissi that date back at least to the 15th century and famous old tulips like 'Duc van Tol' (1595) and its sports.
  2014 September 26, Charles Quest-Ritson, “The Dutch garden where tulip bulbs live forever: Hortus Bulborum, a volunteer-run Dutch garden, is dedicated to conserving historic varieties before they vanish for good ”, in The Daily Telegraph (Gardening)‎
  In a paper published Thursday in the journal Science, a team of researchers say they analyzed the genetic code of nearly 400 varieties of tomatoes ― from the common red supermarket types to the funky heirlooms found in farmers markets.
  2017 January 26, Nick Visser, “Scientists Say Something Is Very Wrong With The Tomato”, in HuffPost‎