What is the ecliptic, and why is it tilted with respect to the celestial equator?

The ecliptic is the line in the celestial sphere traced out by the sun as the rotates (the path in the sky that the sun takes over head during one 24hr day). The celestial equator is just the extension of the regular equator on the surface of the earth.

This means that there will be a "tilt" between the ecliptic and the celestial equator that depends on your latitude of the observers location on the earths surface.

source: astrophysicist