e/Xallarap

Information
has gloss	eng: Xallarap is a variation in a gravitational lensing observation caused by the orbital motion of the source. A more traditional and similar effect, parallax, is the variation caused by motion of the earth around the sun. Since the two effects are converses of each other, this led to the name xallarap, which is parallax spelled backwards. A survey of microlensing attributes the first use in print to Bennett in 1998, though informal usage likely preceded this.
lexicalization	eng: xallarap
instance of	c/Effects of gravitation