Inferior conjunction

When several planets are apparently in the same azimuth, they are said to be in conjunction.

If the Sun is involved it is called a solar conjunction.

For the inner planets, which are those within the Earth's orbit, that is, Mercury and Venus, there are two conjunctions: the superior and the inferior.

In the upper part the planet is behind the Sun (as seen from Earth); in the bottom the planet is in front of the Sun.

For example, the inferior solar conjunction of Mercury means that Earth, Mercury and the Sun are aligned. Mercury is in front of the Sun.