A(n) ellipsis (a word understood but omitted in the sentence) is denoted in a diagram by an x.

the sun warms our planet, and with the moon, creates the tides. the moon orbits the earth and in turn, the earth orbits the sun. because they appear to be the same size in the sky, the sun, earth and moon work together to create eclipses. when the moon is directly in between the earth and sun

whats the underlined word