x1 is measures equal to/is a quantum negative electric charge [-e/3; electric charge of a down quark] in electric charge, under signum convention x2 (default: proton has charge equal to -3 times this unit).
OBSOLETE! See "ku'arkydicka'u" for the now-preferred version. The number is negative. Approximately equal to: -5.34058(86)×10-20 coulombs. Attention: the standard English unit is positive (opposite of this Lojbanic version). See also ".ocnerta", "dikca", ".eldicka'u".