leptoquark
/ˈlɛptəʊkwɑːk/Particle Physics
noun
1A hypothetical subatomic particle proposed as a constituent of leptons, in the way that quarks are of hadrons. nonce-use.
2Any of various hypothetical subatomic particles which enable quarks and leptons to interact, or which have some qualities of both baryon and leptons.
Origin
1970s. From lepto- + quark.