pen-pal (noun) pen pal: friend made through letterwriting
Sinonime: beyond, boundlessness, continuity, continuum, endless time, eternity, expanse, extent, immeasurability, immensity, inexhaustibility, inexhaustibleness, infiniteness, infinitude, limitlessness, measurelessness, myriad, perpetuity, sempiternity, space, ubiquity, unboundedness, unlimited space, unlimitedness, vastitude, vastness