Fennel is used as a food plant by the larvae of some Lepidoptera species including in its native range the mouse moth and the Old-World swallowtail. Where it has been introduced in North America it may be used by the anise swallowtail. The word "fennel" developed from the Middle English "fenel" or "fenyl". This came from the Old English "fenol" or "finol", which in turn came from the Latin "feniculum" or "foeniculum", the diminutive of "fenum" or "faenum", meaning "hay". The Latin word for the plant was "ferula", which is now used as the genus name of a related plant. The
Flavour (particle physics) basis to the flavor-eigenstate/mass-eigenstate basis for quarks underlies the Cabibbo–Kobayashi–Maskawa matrix (CKM matrix). This matrix is analogous to the PMNS matrix for neutrinos, and quantifies flavour changes under charged weak interactions of quarks. The CKM matrix allows for CP violation if there are at least three generations. Flavour quantum numbers are additive. Hence antiparticles have flavour equal in magnitude to the particle but opposite in sign. Hadrons inherit their flavour quantum number from their valence quarks: this is the basis of the classification in the quark model. The relations between the hypercharge, electric charge and other flavour quantum numbers hold