The glossary itself lives at wikipepper.org/glossary, where 183 terms sit in one searchable alphabetical list. This page does the other job: it explains why pepper vocabulary contradicts itself, which words people use interchangeably when they should not, and how to read the letter codes on a seed packet. Start with the list when you need a definition. Start here when the definitions disagree.

What is the difference between chile, chili and chilli?

Spelling, region and sometimes the dish. Chile is the Spanish spelling, standard in Mexico and in the American Southwest, and it is what New Mexico State University uses in its publications. Chili is the usual American spelling, and in most of the United States it also names a bowl of stewed meat and beans, which is a permanent source of confusion. Chilli is the British and Commonwealth spelling. All three descend from the Nahuatl word chilli, and none of them is wrong.

Two other regionalisms trip people up. Aji is the South American word for the same thing, from Taino by way of Spanish, and it carries no species meaning. Capsicum, in Britain, Australia, India and New Zealand, usually means a sweet bell pepper at the greengrocer, while in botany it means the whole genus. And pepper itself is a historical accident: Columbus reached for the name of Piper nigrum, the unrelated vine that produces black peppercorns, and it stuck.

Terms people swap that mean different things

Species, botanical variety, cultivar, landrace, strain and accession describe different kinds of category, and the difference determines whether your saved seed comes back true. A species is biological. A cultivar is a human selection with a name governed by the International Code of Nomenclature for Cultivated Plants, written in single quotes and never italicized. A landrace is a diverse local population. An accession is one numbered sample in a genebank. Our article on species, landraces, cultivars and accessions works through all of them.

Two more pairs worth separating. Heirloom and open-pollinated are not synonyms: every heirloom is open-pollinated, but a variety released last year is open-pollinated and not an heirloom. Pungency and heat are the same property under two names, one of them botanical, and both refer to capsaicinoid content rather than to flavor.

What do the letters and numbers in a pepper name mean?

Most of them fall into two groups: genebank prefixes, which identify a sample held in a collection, and community shorthand, which identifies a breeder, an institution or a parent variety.

Prefix.Who issues it.Example and note.
PI.USDA National Plant Germplasm System, searchable in GRIN.Plant Introduction number. Permanent and unambiguous. PI 257068 and PI 260535 both travel as Aji Picante and are different plants.
GRIF.USDA NPGS, for material held without a PI assignment.Works the same way as a PI number for identification purposes.
CGN.Centre for Genetic Resources, the Netherlands.Europe's most photographed pepper collection, strong on morphological documentation.
CAP.Genebank of the Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany, institute code DEU146.Several CAP numbers circulate in the hobby trade as variety names. The site glossary currently credits these to the Chile Pepper Institute; Genesys and IPK place them at Gatersleben.
TWN001 collection.World Vegetable Center, Taiwan.The largest single Capsicum holding, about 9,000 accessions listed in Genesys, strong on Asian material.

The rule behind all of them: when a name carries an accession number, the number is the identity and the name is decoration.

Breeder and seller shorthand

Code.Meaning.
F1.First generation from two distinct stable parents. Uniform, vigorous, and will not come true from saved seed.
F2 through F8.Successive generations after a cross. F2 segregates hardest; a line usually breeds true around F7 or F8.
Bx, BC.Backcross. A hybrid crossed back to one parent to pull a single trait across.
OP.Open-pollinated. Comes true from seed if you isolate it.
x, or the multiplication sign.A cross. The seed parent conventionally comes first.
NuMex.A cultivar released by New Mexico State University.
TAM.A cultivar released by Texas A&M.
MOA.Jamaica's Ministry of Agriculture, on Scotch Bonnet selections.
KS.Khang Starr, a prolific hobby breeder, on his crosses.
BBG7.Bubblegum 7 Pot, a superhot C. chinense known for a bleeding calyx.
BOC.Bhut Orange Copenhagen, a selection out of Bhut Jolokia.
JPN.7 Pot Jonah crossed with Pimenta de Neyde, a common parent in dark-podded lines.
Peach, chocolate, mustard.Color descriptors, not lineage. The same word attaches to unrelated plants.

Heat words

SHU stands for Scoville Heat Unit, and it reports capsaicinoid content measured by liquid chromatography, scaled to a number. A bell pepper rates 0. Superhot is not a botanical category: the community uses it for anything above a million SHU, which in practice means a handful of C. chinense lines. Browse them on the superhot list, and the varieties with no measurable capsaicin on the no-heat list. Capsaicin is one compound; capsaicinoid is the family it belongs to, and the mix inside a pod changes how the burn arrives and how long it stays. The Scoville guide and capsaicin and capsaicinoids cover the chemistry.

WikiPepper adds one more code on top. Every record carries a Universal Pepper Number, a string encoding species, color, pattern, pod form and a heat digit from 0 to 9. Two sellers arguing about what a variety is can compare UPN codes instead of adjectives.

Plant parts, in the words the references use

The calyx is the green collar at the top of the pod, and in C. chinense it carries a pinched ring where it meets the stem, which is the fastest species identification in the genus. The corolla is the ring of petals: white in C. annuum, white with greenish-yellow spots in C. baccatum, purple in C. pubescens. Anthesis is the moment a flower opens and can accept pollen. The placenta is the pale tissue holding the seeds, and it carries far more capsaicin than the flesh or the skin. Pericarp, exocarp, mesocarp and endocarp are the wall of the pod, outside to inside. The anatomy guide has the diagrams.

When two names mean one plant

Duplicate naming is the deepest problem in pepper vocabulary, and no glossary fixes it. The same plant reaches you as Bhut Jolokia and as Ghost Pepper; Scotch Bonnet covers several distinct Jamaican landraces; Trinidad Scorpion names a group of selections rather than one variety. Our running list of alternative names for identical peppers tracks the pairs, and searching the database by both names usually settles the question faster than arguing about it.

Sources & Further Reading