EFFLUX is a 6 letter word that starts with E.

1. \Ef"flux\, n. [See {Effluent}, {Flux}.]
   1. The act or process of flowing out, or issuing forth;
      effusion; outflow; as, the efflux of matter from an ulcer;
      the efflux of men's piety.
   
            It is then that the devout affections . . . are
            incessantly in efflux.                --I. Taylor.
   
   2. That which flows out; emanation; effluence.
   
            Prime cheerer, light! . . . Efflux divine.
                                                  --Thomson.
   
   

2. \Ef*flux"\, v. i.
   To run out; to flow forth; to pass away. [Obs.] --Boyle.