electron neutrino

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The neutrino that is associated with the electron in weak interactions, and has an extremely small mass of less than 4 × 10⁻⁶ times that of an electron.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A leptonic elementary particle, having near-zero mass and no charge