Definition of polytype in English:

polytype

noun

Crystallography
  • Any of a number of forms of a crystalline substance that differ in only one of the dimensions of the unit cell.

    • ‘There are four polytypes known.’
    • ‘Microcrystals of the following polytypes were identified: 4H, 6H, 15R, and 18R.’
    • ‘The high-temperature polytype dickite is also present in the immediate vicinity of the thrust planes.’
    • ‘Several polytypes of wurtzite were reported at the Negley and Alikanna sites.’

Pronunciation:

polytype

/ˈpälēˌtīp/