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) , which is − for the three charged leptons (i.e. electron, muon and tau) and + for the three associated neutrinos. Each doublet of a charged lepton and a neutrino consisting of opposite are said to constitute one generation of leptons. In addition, one defines a quantum number called weak hypercharge, , which is −1 for all left-handed leptons. Weak isospin and weak hypercharge are gauged in the Standard Model. Leptons may be assigned the six flavour quantum numbers: electron number, muon number, tau number, and corresponding numbers for the neutrinos. These are conserved in strong and electromagnetic interactions, but