conjunction

In astronomy, alignment of two celestial bodies as seen from Earth. A superior planet (or other object) is in conjunction when it lies behind the Sun. An inferior planet (or other object) comes to inferior conjunction when it passes between the Earth and the Sun; it is at superior conjunction when it passes behind the Sun.

Planetary conjunction takes place when a planet is closely aligned with another celestial object, such as the Moon, a star, or another planet.

Because the orbital planes of the inferior planets are tilted with respect to that of the Earth, they usually pass either above or below the Sun at inferior conjunction. If they line up exactly, a transit will occur.

conjunction

Grammatical part of speech that serves to connect words, phrases, and clauses.

Coordinating conjunctions link parts of equal grammatical value; and, but, and or are the most common.

Subordinating conjunctions link subordinate clauses to the main clause in a sentence; among the most common are if, when, and though.

It is not considered good style to use too many conjunctions (particularly the same one repeatedly) in a sentence. Punctuation, especially commas (,) and semi-colons (;) can also connect clauses. A semi-colon is used to join sentences with closely related subjects, as in ‘John is sitting; his sister is standing.’ Writers commonly use a comma here, which is incorrect.