Symbology for elliptic multiple polylogarithms and the symbol prime

A bstract Elliptic multiple polylogarithms occur in Feynman integrals and particular scattering amplitudes. They can be characterized by their symbol, a tensor product the so-called symbol letters. In contrast to non-elliptic case, elliptic letters themselves satisfy highly non-trivial identities, which we discuss this paper. Moreover, introduce prime, an analog of for letters, makes these identities manifest. We demonstrate its use two explicit examples at two-loop order: unequal-mass sunrise integral dimensions ten-point double-box four dimensions. Finally, also report result polylogarithmic nine-point integral, arises as soft limit integral.