Kil'ayim (prohibition)

Kil'ayim (or Klayim) (Hebrew: כלאים‎‎, lit. "Mixture," or "Confusion," or "Diverse kinds") is the Torah-based prohibition of crossbreeding seeds, crossbreeding animals, and mixing wool and linen.

Permissive instances

Although Torah law forbids klayim (shatnez) – "intertying" wool and linen together, with the two exceptions being garments of kohanim and tzitit. Concerning tzitzit, chazal permit using wool and linen strings in tandem only when genuine tchelet is available, whereas kabbalist sources take it a step further by encouraging its practice.^[1] However, klayim of animals and seeds are essentially excluded from any permissive instances.

References